misc changes to SongSearcher
created the MusicController class
changed the implementation of ApiMusicImpl to implement Singleton Pattern
finished the implementation of MusicController
commented the MusicController class
Merge https://github.com/LO23/BitMusic
changed method SongSearcher.searchSongsbyUser with call to the network ApiMusic
finalised implementation of SongSearcher, need to check some methods
Merge pull request #150 from amina196/master

[music] finalised implementation ApiMusic with Singleton Pattern, and implementation of SongSearcher