Fixed #2467  Fixed a bug of cc.LabelBMFont that it's very slow when calling setString
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into develop_BMFont
Merge pull request #1086 from xingsenma/develop_BMFont

Fixed #2467 Fixed a bug of cc.LabelBMFont that it's very slow when calling setString