Update build instructions.

Also update travis ci to follow the same pattern as in the build
instructions.

.travis.yml

@@ -30,25 +30,24 @@ addons:
     - pkg-config                   #needed for thrift cpp compilation
 
 before_install:
-    - pushd thirdparty
+    - mkdir $HOME/build_dir
+    - cd $HOME/build_dir
     - >
       if [ $TRAVIS_OS_NAME == osx ]; then
         brew update &&
         brew install thrift lz4 snappy;
       fi
     - >
       if [ $TRAVIS_OS_NAME == linux ]; then
-        ./download_thirdparty.sh &&
-        ./build_thirdparty.sh &&
-        export THRIFT_HOME=$TRAVIS_BUILD_DIR/thirdparty/installed SNAPPY_HOME=$TRAVIS_BUILD_DIR/thirdparty/installed LZ4_HOME=$TRAVIS_BUILD_DIR/thirdparty/installed;
+        cp -r $TRAVIS_BUILD_DIR/thirdparty . &&
+        ./thirdparty/download_thirdparty.sh &&
+        ./thirdparty/build_thirdparty.sh &&
+        export THRIFT_HOME=$HOME/build_dir/thirdparty/installed SNAPPY_HOME=$HOME/build_dir/thirdparty/installed LZ4_HOME=$HOME/build_dir/thirdparty/installed;
       fi
-    - popd
 
 before_script:
     - export CC="gcc-4.9"
     - export CXX="g++-4.9"
-    - mkdir build
-    - cd build
-    - cmake ..
+    - cmake $TRAVIS_BUILD_DIR
 
 script: make

README.md

@@ -2,30 +2,43 @@ Parquet-cpp [![Build Status](https://travis-ci.org/apache/parquet-cpp.svg)](http
 ===========
 A C++ library to read parquet files.
 
-To build you will need all the dependencies for thrift.
-
-Then run:
-<br>
-<code>
-./thirdparty/download_thirdparty.sh
-</code>
-<br>
-<code>
-./thirdparty/build_thirdparty.sh
-</code>
-<br>
-<code>
-THRIFT_HOME=$PWD/thirdparty/installed/ cmake -D CMAKE_PREFIX_PATH=$PWD/thirdparty/installed/ . 
-</code>
-<br>
-<code>
-make
-</code>
+## Third Party Dependencies
+- snappy
+- lz4
+- thrift 0.7+ [install instructions](https://thrift.apache.org/docs/install/)
+
+Many package managers support some or all of these dependencies. E.g.:
+```shell
+ubuntu$ sudo apt-get install libboost-dev libsnappy-dev liblz4-dev
+```
+```shell
+mac$ brew install boost snappy lz4 thrift
+```
+
+The thirdparty directory contains helper scripts to manually install third-party dependencies on Linux. You can use them like so.
+- `mkdir <build-dir>`
+- `cd <build-dir>`
+- `cp -r <src-dir>/thirdparty .`
+- `./thirdparty/download_thirdparty.sh`
+- `./thirdparty/build_thirdparty.sh`
+- Use the thirdparty/installed directory when configuring HOME dirs for dependencies.
+Ex., `THRIFT_HOME=$PWD/thirdparty/installed SNAPPY_HOME=$PWD/thirdparty/installed LZ4_HOME=$PWD/thirdparty/installed cmake <source_dir>`
+
+You can also take a look at our [.travis.yml](.travis.yml) to see how that build env is set up.
+
+
+## Build
+- `cmake .`
+  - You can customize dependent library locations through various environment variables:
+    - THRIFT_HOME customizes the thrift installed location.
+    - SNAPPY_HOME customizes the snappy installed location.
+    - LZ4_HOME customizes the lz4 installed location.
+- `make`
 
 The binaries will be built to ./debug which contains the libraries to link against as
 well as a few example executables.
 
-Incremental builds can be done afterwords with just <code> make </code>.
+Incremental builds can be done afterwords with just `make`.
 
 Design
 ========