Refactor functions of log.
cc.renderContextType --> cc.renderType.
cc.CANVAS --> cc.RENDER_TYPE_CANVAS.
cc.WEBGL --> cc.RENDER_TYPE_WEBGL.
Merge branch 'develop-3.0' of https://github.com/cocos2d/cocos2d-html5 into CCGame_dev3.0
Refactor functions of log.
cc.renderContextType --> cc.renderType.
cc.CANVAS --> cc.RENDER_TYPE_CANVAS.
cc.WEBGL --> cc.RENDER_TYPE_WEBGL.
Merge pull request #1618 from SmallAiTT/CCGame_dev3.0

Refactor functions of log.