Add CCGroupCommand which allows for rendering of RenderCommands in a group.
Add CCGroupCommand which allows for rendering of RenderCommands in a group.

MSylvia/CocosSharp,zmaruo/CocosSharp,zmaruo/CocosSharp,haithemaraissia/CocosSharp,haithemaraissia/CocosSharp,mono/CocosSharp,TukekeSoft/CocosSharp,MSylvia/CocosSharp,mono/CocosSharp,TukekeSoft/CocosSharp