MenuItemToggle is fixed

Supports callbacks now.
Updated MenuTest to supports the new API.
Updated CHANGELOG and version
Updatged Xcode project for Mac
Merge branch 'menuitem_toggle_fixes' of https://github.com/ricardoquesada/cocos2d-x into ricardoquesada-menuitem_toggle_fixes
Reverting target to android-8.
Don't generate js binding glue code for CCMenuItem.*::initWithCallback.
Merge pull request #2787 from dumganhar/ricardoquesada-menuitem_toggle_fixes

Merge PR https://github.com/cocos2d/cocos2d-x/pull/2777