设置音乐

Signed-off-by: Zhao Yanxia <1716655706@qq.com>
Merge branch 'master' of https://github.com/Cocos2dxGame/MHE
修复暂停游戏开始会使音乐播放的bug。完成帮助场景

Signed-off-by: Zhao Yanxia <1716655706@qq.com>