cocos播放音频（jsb.AudioEngine.play2d）是不是一定要.mp3这样的后缀，貌似我去了后缀就播放不了了，log如下
V/AudioCache (71): AudioCache() 1300EE44, id=1
V/AudioCache (129): readDataTask begin, cache id=1
D/AudioEngine-Win32 (280): AudioEngineImpl::_play2d, cache was destroyed or not ready!
V/AudioCache (294): readDataTask end, cache id=1