Base stubs for CRUD Operations

Method Stubs, currently filling them in for:
Add song to playlist
Remove song from playlist
Context menu to add song to/remove from playlist
Remove Song From Playlist

(Theoretically) Right click a song on the screen and simply select
"Remove from playlist".
Merge remote-tracking branch 'origin/master'

Conflicts:
	Cloudmp3/Cloudmp3/MainWindow.xaml.cs