fix for creation of proxies during poly test where an index out of bounds exception can occur.
Merge pull request #311 from mono/master

Add Frames property, ths[string] indexer and fixed typo.
Merge pull request #310 from Cocos2DXNA/FIXTURE_PROXY_FIX

fix for creation of proxies during poly test where an index out of bound...
Merge pull request #312 from mono/master

Fix build to compile on Mac.  Finally
Add Binary Plist format reader and support for Sprite Kit atlas to CCSpriteSheet.