added information about OperatingSystem and Version to AddInSystemFactory
added IsSupported field to AddIn Creators
AddInSystemFactory now only loads supported AddIns
added Metadata resource files to all AddIns containing information about supported platforms.
added build folder
added build script for release build of ANX.Framework and all RenderSystems
fixed some issues in projects regarding compiler directives
removed StockShaderCodeGenerator from Pre-Build-Events. Build the Stock shaders using NAnt target build_stock_shaders.
started Wiki documentation for custom build switches (e.g. extended mode)