Added playlists support
fixed context menu actions
Fixed Playlist name displaying
Limit web cover requests (for big playlists scrolling)
Discard oldest web cover requests when a maximum size has been reached
Avoid to overload the web cover request queue when scrolling a big playlist.
Efficient enough without having to get the scrolling status
Merge pull request #298 from jcnoir/limit-web-requests

Limit web cover requests (for big playlists scrolling)
Merge branch 'master' of https://github.com/abarisain/dmix