move Documentation up in the readme

the documentation is kinda the most important part so let's put the important things first.

README.md

@@ -5,6 +5,10 @@
 
 Copyright 2015 Google Inc.
 
+#Documentation
+
+You can find more detailed documentation and examples in the [grpc-common repository](http://github.com/grpc/grpc-common).
+
 #Installation
 
 See grpc/INSTALL for installation instructions for various platforms.
@@ -25,10 +29,6 @@ of shared C core library [src/core] (src/core).
 Java source code is in [grpc-java] (http://github.com/grpc/grpc-java) repository. 
 Go source code is in [grpc-go] (http://github.com/grpc/grpc-go) repository.
 
-#Documentation
-
-You can find more detailed documentation and examples in the [grpc-common repository](http://github.com/grpc/grpc-common).
-
 #Current Status of libraries
 
 Libraries in different languages are in different state of development. We are seeking contributions for all of these libraries.