[mythtv] patch: playlist updates

[Andy Davidoff]

#if Isaac Richards /* Feb 24, 11:31 */
> Existing playlists are just what's been saved when the user exits mythmusic -- 
> they're easily recreatable.  I don't really care if the single automatically 
> generated playlist in the db gets blown away.

fixschema was for mdz, not you. :-)

> Other stuff:  The default playlist is _always_ going to get saved and loaded 
> at the load/exit of mythmusic, so there's really no need for a specific 
> setting in the db for it.  It should be host specific, though, but that can 
> be accomplished in the same manner that the rest of the settings are, just a 
> hostname field in the musicplaylist table.
#endif /* ijr at po.cwru.edu */

Someone requested per-host playlists and a toggle for "exporting" such
playlists to global scope -- hence the hostname field in musicplaylist.

The specific setting in the DB lets us remember which playlist a host was
last listening to so that it loads that playlist when starting mythmusic.
This is almost verbatim what you wrote above, but it uses the existing
per-host/global settings framework, which is an exactly identical model.