Send device name header to myPlex, fixes #245.
Only ever create a single object for each server, fixes #244.

When testing multiple connections, only create a single server object to
make sure that nothing is left holding a reference to the wrong instance.
Add interval to PMS BIF requests, fixes #246.

Hardcoded (well, hidden pref) to 10 seconds for now.
Fix crash on playback on 3.x firmware, fixes #247.
Rename transcoder options.

We don't quite seem ready to remove the option completely, but we can at least
make the universal transcoder seem less dangerous.
[Stable, Experimental] -> [Legacy, Universal]
Don't annotate video title once playback starts, fixes #248.
Allow audio player looping to be set from the springboard.