Fix Regression Compile errors for Windows.  Game.ExitGame() is no longer available for certain platforms.
Fix Regression Compile errors for Windows.  Game.ExitGame() is no longer available for certain platforms.

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