Updated MonoDevelop addin to work with latest version and Xamarin Studio

* Updated MonoDevelop addin to work with latest version (3.0.4) of MD /
XS
* Removed unnecessary files from lib/monodevelop
Fixed MonoDevelop addin category

* Moved MonoDevelop addin from "Ide extenstions" to "Testing" category.
Added Syntax Highlighting to MonoDevelop addin