Fix problem with disappearing Statistics when TextureCache is purged.
Fix problem with disappearing Statistics when TextureCache is purged.

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