Fix handling of contentScaleFactor != 1

fixes for Sprite, scale9Sprite, and LabelTTF.
performance improvement for contentScaleFactor fix in Sprite.draw
Merge remote-tracking branch 'upstream/develop' into contantScaleFactorFixes
Merge branch 'contantScaleFactorFixes' of https://github.com/MarkEHenderson/cocos2d-html5 into ContentScaleFactorNotEqual1
Test ContentScaleFactor NotEqual 1
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into ContentScaleFactorNotEqual1
Fix handling of contentScaleFactor != 1
Merge pull request #1037 from dingpinglv/ContentScaleFactorNotEqual1

Fix handling of contentScaleFactor != 1