Merge pull request #2861 from dumganhar/master

[emscripten] Updating extension makefile.
Fixing a logic error in CCDirector.cpp.
Fixing a bug that vs express can't work. Reported at https://github.com/cocos2d/cocos2d-x/issues/2859
Merge branch 'master' of https://github.com/cocos2d/cocos2d-x