Fix NRE in CCMusicPlayer Mac and iOS.  If music is null we just return from methods.
Fix NRE in CCMusicPlayer Mac and iOS.  If music is null we just return from methods.

hig-ag/CocosSharp,netonjm/CocosSharp,TukekeSoft/CocosSharp,mono/CocosSharp,hig-ag/CocosSharp,zmaruo/CocosSharp,mono/CocosSharp,haithemaraissia/CocosSharp,MSylvia/CocosSharp,MSylvia/CocosSharp,haithemaraissia/CocosSharp,TukekeSoft/CocosSharp,netonjm/CocosSharp,zmaruo/CocosSharp