Set a default player in settings

[kaaholst]

Hi,

it would be nice if I could configure a default player in the settings. This player
should be chosen automatically on app start up, if it is available.

Situation is as follows:
With my living room tablet I usually want to control my living room stereo, not the
bath room nor the kitchen player or anything else. Squeezer AFAIK remembers the last
chosen player, but not if the player was shut down in the mean time. So if I power
of my living room stereo the player changes to another player and I always have to
change it myself again.

Original issue reported on code.google.com by thenktor on 2014-12-03 11:15:41