Merge pull request #525 from learn-more/add_link

Add link from the documentation to the code

src/HEADER

@@ -47,6 +47,7 @@
 /// - No global or hidden state
 /// - Customizable library modules (you can compile and use only what you need)
 /// - Optional font baker and vertex buffer output
+/// - [Code available on github](https://github.com/Immediate-Mode-UI/Nuklear/)
 ///
 /// ## Features
 /// - Absolutely no platform dependent code