Auto merge of #93 - MichaelHirn:book, r=MichaelHirn

[WIP] The 'Leaf: Machine Learning for hackers' book

This PR is a work in progress. So far I added the 1. Leaf and 2. Layers chapters.

Feedback for the overall structure of the book as well as the general ideas and style of the first two chapters are highly welcome.

There are probably a lot of typos and grammar mistakes in there. You don't have to bother yet pointing them out, the text might change quickly.

REFERENCE: #91

README.md

@@ -2,44 +2,40 @@
 
 ## Introduction
 
-Leaf is a Machine Intelligence Framework engineered by software developers, not
-scientists. It was inspired by the brilliant people behind TensorFlow, Torch,
-Caffe, Rust and numerous research papers and brings modularity, performance and
-portability to deep learning. Leaf is lean and tries to introduce minimal
+Leaf is a open Machine Learning Framework for hackers to build classical, deep
+or hybrid machine learning applications. It was inspired by the brilliant people
+behind TensorFlow, Torch, Caffe, Rust and numerous research papers and brings
+modularity, performance and portability to deep learning.
+
+Leaf has one of the simplest APIs, is lean and tries to introduce minimal
 technical debt to your stack.
 
-Leaf is a few months old, but thanks to its architecture and Rust, it is already one of
-the fastest Machine Intelligence Frameworks in the world.
+Leaf is a few months old, but thanks to its architecture and Rust, it is already
+one of the fastest Machine Intelligence Frameworks available.
 
 <div align="center">
   <img src="http://autumnai.com/images/autumn_leaf_benchmarks_alexnet.png"><br><br>
 </div>
 
 > See more Deep Neural Networks benchmarks on [Deep Learning Benchmarks][deep-learning-benchmarks-website].
 
-Leaf is portable. Run it on CPUs, GPUs, FPGAs on machines with an OS or on
+Leaf is portable. Run it on CPUs, GPUs, and FPGAs, on machines with an OS, or on
 machines without one. Run it with OpenCL or CUDA. Credit goes to
 [Collenchyma][collenchyma] and Rust.
 
 Leaf is part of the [Autumn][autumn] Machine Intelligence Platform, which is
-working on making AI algorithms 100x more computational efficient. It seeks to bring
-real-time, offline AI to smartphones and embedded devices.
+working on making AI algorithms 100x more computational efficient.
 
 We see Leaf as the core of constructing high-performance machine intelligence
 applications. Leaf's design makes it easy to publish independent modules to make
 e.g. deep reinforcement learning, visualization and monitoring, network
 distribution, [automated preprocessing][cuticula] or scaleable production
 deployment easily accessible for everyone.
 
-For more info, refer to
-* the [Leaf examples][leaf-examples],
-* the [Leaf Documentation][documentation],
-* the [Autumn Website][autumn] or
-* the [Q&A](#qa)
-
 [caffe]: https://github.com/BVLC/caffe
 [rust]: https://www.rust-lang.org/
 [autumn]: http://autumnai.com
+[leaf-book]: http://autumnai.com/leaf/book
 [tensorflow]: https://github.com/tensorflow/tensorflow
 [benchmarks]: #benchmarks
 [leaf-examples]: #examples
@@ -52,22 +48,42 @@ For more info, refer to
 
 ## Getting Started
 
-If you are new to Rust you can install it as detailed [here][rust_download].
-We also recommend taking a look at the [official Getting Started Guide][rust_getting_started].
+### Documentation
+
+To learn how to build classical, deep or hybrid machine learning applications with Leaf, check out the [Leaf - Machine Learning for Hackers][leaf-book] book.
+
+For additional information see the [Rust API Documentation][documentation] or the [Autumn Website][autumn].
+
+Or start by running the **Leaf examples**.
 
-If you're using Cargo, just add Leaf to your `Cargo.toml`:
+We are providing a [Leaf examples repository][leaf-examples], where we and
+others publish executable machine learning models build with Leaf. It features
+a CLI for easy usage and has a detailed guide in the [project
+README.md][leaf-examples].
+
+Leaf comes with an examples directory as well, which features popular neural
+networks (e.g. Alexnet, Overfeat, VGG). To run them on your machine, just follow
+the install guide, clone this repoistory and then run
+
+```bash
+# The examples currently require CUDA support.
+cargo run --release --no-default-features --features cuda --example benchmarks alexnet
+```
+
+[leaf-examples]: https://github.com/autumnai/leaf-examples
+
+### Installation
+
+> Leaf is build in [Rust][rust]. If you are new to Rust you can install Rust as detailed [here][rust_download].
+We also recommend taking a look at the [official Rust - Getting Started Guide][rust_getting_started].
+
+To start building a machine learning application (Rust only for now. Wrappers are welcome) and you are using Cargo, just add Leaf to your `Cargo.toml`:
 
 ```toml
 [dependencies]
 leaf = "0.2.0"
 ```
 
-If you're using [Cargo Edit][cargo-edit], you can
-call:
-
-```bash
-cargo add leaf
-```
 [rust_download]: https://www.rust-lang.org/downloads.html
 [rust_getting_started]: https://doc.rust-lang.org/book/getting-started.html
 [cargo-edit]: https://github.com/killercup/cargo-edit
@@ -88,24 +104,24 @@ opencl  = ["leaf/opencl"]
 
 > More information on the use of feature flags in Leaf can be found in [FEATURE-FLAGS.md](./FEATURE-FLAGS.md)
 
+### Contributing
 
-## Examples
+If you want to start hacking on Leaf (e.g.
+  [adding a new `Layer`](http://autumnai.com/leaf/book/create-new-layer.html))
+you should start with forking and cloning the repository.
 
-We are providing a [Leaf examples repository][leaf-examples], where we and
-others publish executable machine learning models build with Leaf. It features
-a CLI for easy usage and has a detailed guide in the [project
-README.md][leaf-examples].
+We have more instructions to help you get started in the [CONTRIBUTING.md][contributing].
 
-Leaf comes with an examples directory as well, which features popular neural
-networks (e.g. Alexnet, Overfeat, VGG). To run them on your machine, just follow
-the install guide, clone this repoistory and then run
+We also has a near real-time collaboration culture, which happens
+here on Github and on the [Leaf Gitter Channel][gitter-leaf].
 
-```bash
-# The examples currently require CUDA support.
-cargo run --release --no-default-features --features cuda --example benchmarks alexnet
-```
+> Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as below, without any additional terms or conditions.
 
-[leaf-examples]: https://github.com/autumnai/leaf-examples
+[contributing]: CONTRIBUTING.md
+[gitter-leaf]: https://gitter.im/autumnai/leaf
+[mj]: https://twitter.com/mjhirn
+[hobofan]: https://twitter.com/hobofan
+[irc]: https://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-machine-learning
 
 ## Ecosystem / Extensions
 
@@ -120,84 +136,21 @@ and extensible as possible. More helpful crates you can use with Leaf:
 
 ## Support / Contact
 
-- With a bit of luck, you can find us online on the #rust-machine-learing IRC at irc.mozilla.org,
+- With a bit of luck, you can find us online on the #rust-machine-learning IRC at irc.mozilla.org,
 - but we are always approachable on [Gitter/Leaf][gitter-leaf]
 - For bugs and feature request, you can create a [Github issue][leaf-issue]
 - For more private matters, send us email straight to our inbox: developers@autumnai.com
 - Refer to [Autumn][autumn] for more information
 
 [leaf-issue]: https://github.com/autumnai/leaf/issues
 
-## Contributing
-
-Want to contribute? Awesome! We have [instructions to help you get started][contributing].
-
-Leaf has a near real-time collaboration culture, and it happens here on Github and
-on the [Leaf Gitter Channel][gitter-leaf].
-
-Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0
-license, shall be dual licensed as below, without any additional terms or
-conditions.
-
-[contributing]: CONTRIBUTING.md
-[gitter-leaf]: https://gitter.im/autumnai/leaf
-[mj]: https://twitter.com/mjhirn
-[hobofan]: https://twitter.com/hobofan
-[irc]: https://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-machine-learning
-
 ## Changelog
 
 You can find the release history at the [CHANGELOG.md][changelog]. We are using [Clog][clog], the Rust tool for auto-generating CHANGELOG files.
 
 [changelog]: CHANGELOG.md
 [Clog]: https://github.com/clog-tool/clog-cli
 
-## Q&A
-
-#### _Why Rust?_
-
-Hardware has just recently become strong enough to support real-world
-usage of machine intelligence e.g. super-human image recognition, self-driving
-cars, etc. To take advantage of the computational power of the underlying
-hardware, from GPUs to clusters, you need a low-level language that allows for
-control of memory. But to make machine intelligence widely accessible you want
-to have a high-level, comfortable abstraction over the underlying hardware.
-
-Rust allows us to cross this chasm.
-Rust promises performance like C/C++ but with safe memory-control. For now we
-can use C Rust wrappers for performant libraries. But in the future Rust
-rewritten libraries will have the advantage of zero-cost safe memory control,
-that will make large, parallel learning networks over CPUs and GPUs more
-feasible and more reliable to develop. The development of these future libraries
-is already under way e.g. [Glium][glium].
-
-On the usability side, Rust offers a trait-system that makes it easy for
-researchers and hobbyists alike to extend and work with Leaf as if it were
-written in a higher-level language such as Ruby, Python, or Java.
-
-#### _Who can use Leaf?_
-
-We develop Leaf under the MIT open source license, which, paired with the easy
-access and performance, makes Leaf a first-choice option for researchers and
-developers alike.
-
-#### _Why did you open source Leaf?_
-
-We believe strongly in machine intelligence and think that it will have a major
-impact on future innovations, products and our society. At Autumn, we experienced
-a lack of common and well engineered tools for machine learning and therefore
-started to create a modular toolbox for machine learning in Rust. We hope that,
-by making our work open source, we will speed up research and development of
-production-ready applications and make that work easier as well.
-
-#### _Who is Autumn?_
-
-Autumn is a startup working on automated decision making. Autumn was started by
-two developers, MJ and Max. The startup is located in Berlin and recently
-received a pre-seed investment from Axel Springer and Plug&Play.
-
-[glium]: https://github.com/tomaka/glium
-
 ## License
 
 Licensed under either of