Merge pull request #1142 from dingpinglv/Iss2803_V2.1.6Release

Issue #2803: fixed a bug for cc.Sprite that its drawing doesn't work when _rect's width or height greater than 0 and less than 1.
Issue #2803: cc.Sprite's setFlipX, setFlipY have renamed to setFlippedX, setFlippedY
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss2803_V2.1.6Release