Cleanup of CCLayer:
Cleanup of CCLayer:

* replacing ivars with properties where possible
* renaming of private ivars to remove m_ prefix
* reorganising of methods/properties
* general cleanup

hig-ag/CocosSharp,hig-ag/CocosSharp,haithemaraissia/CocosSharp,MSylvia/CocosSharp,mono/CocosSharp,TukekeSoft/CocosSharp,mono/CocosSharp,netonjm/CocosSharp,MSylvia/CocosSharp,haithemaraissia/CocosSharp,zmaruo/CocosSharp,zmaruo/CocosSharp,netonjm/CocosSharp,TukekeSoft/CocosSharp