install docs; light changes to intro.md, core.md; demo/hello.scm

docs/install.md

@@ -0,0 +1,23 @@
+Installing Irken
+================
+
+Irken can be downloaded from its GitHub page.
+
+Clone the `master` branch of the `irken-compiler` repository
+
+    git clone https://github.com/samrushing/irken-compiler.git
+
+Change to the newly created repository directory and run the python bootstrap script
+
+    cd irken-compiler
+    python util/bootstrap.py
+
+Compilation will take a few minutes. If you don't get any error messages, you should be ready for installation. The installation process will install all files under `/usr/local`. To install:
+
+    python util/install.py
+
+Once complete, you can confirm that Irken is installed and ready to use by compiling a simple demo program. Assuming `/usr/local/bin` is in your path:
+
+    irken demo/hello.scm
+    demo/hello
+    Hello, World!

docs/intro.md

@@ -156,7 +156,6 @@ Which can now be called:
 
 ```scheme
 (+ 1 (double x))
-(double (double x))
 ```
 
 Here is a factorial function:

docs/lib/core.md

@@ -1,6 +1,6 @@
 
 The Core Library
-----------------
+================
 
 The 'core' (in `lib/core.scm`) contains the lowest-level primitives, a
 sort of minimal set of features needed by any program.