Music lens should only display results from default music player

If a user has both Banshee and Rhythmbox installed, and the database for both players contains songs, then results for both are returned from each database. This leads to 2 results for each song common to both databases. If the databases have the same album art, then there is no way to distinguish the two results (same image, same song title and same artist) and so way to tell which music player the result is going to open with.

Furthermore, if the user uninstalls a music player and the database is not removed (which it generally is not unless the user manually removes it), duplicate results show up for a music player that is no longer installed.

One solution is to only provide results for the music player that is set as default. In this case there would be no duplicate results. One problem with this approach is that if the user sets a default music player that has no scope available, then the music lens is rendered useless for them.

Another option would be to indicate on each result which music player it is associated with, either using text or by badging the icon with the player's logo. This, however would be superfluous where only one player is installed and may make the lens feel more cluttered.