Updated README.md to contain links to all other documents

README.md

@@ -3,8 +3,7 @@
 - [Installation](#installation)
 - [Usage](#usage)
 - [Issues](#issues)
-- [Theming](#theming)
-- [Building](#building)
+- [Development](#development)
 - [Acknowledgements](#acknowledgements)
 - [License](#license)
 
@@ -162,12 +161,12 @@ of losing data when powering down too quickly. Also note that when *resuming* a
 to a save state if present.
 
 
-# Theming
-Instructions moved to [THEMING.md](THEMING.md).
+# Development
+If you wish to build or modify Retro-Go, you can find help in the following documents:
 
-
-# Building
-Instructions moved to [BUILDING.md](BUILDING.md).
+- Build instructions in [BUILDING.md](BUILDING.md)
+- Theming instructions [THEMING.md](THEMING.md)
+- Porting instructions in [PORTING.md](PORTING.md)
 
 
 # Acknowledgements