Zambiorix integrate sharp zlib

added SharpZlib code in iOS, MACOS & Android projects and updated the namespace to Cocos2D.Compression.ICSharpCode.SharpZipLib (only for iOS, MACOS & Android)

=> this follows the same approach as zlib.dll (code has also been integrated, removing the need to use an extra dependancy)
=> other platforms need to do the same
=> XBOX uses a special build, must be taken care of

I can't currently update other platforms (I'm on a Mac), but will look into them when I have access to a Windows PC