Refactore code that tags album cover with artist and album
Make it more robust to changes
Fix for : Playlist item covers may get mixed up when items have the same title.
=> Add artist + album to the item view tag to avoid confusion.
Improve robustness to temporary network problems.
Perform several attempts before warning the user that the network is not available.
Fix : Cannot load tracks from album name with double quotes
=> Escape the double quotes
 Before this commit :
 find "artist" "Keith Anderson" "album" "Full of Soul "Live at Ovations""
 After this commit :
 find "artist" "Keith Anderson" "album" "Full of Soul \"Live at Ovations\""

 N.B :To be tested with Mopidy
Fix for locale cover fetcher
- Set path and filename from the playlist fragment