[mythtv] mythvideo DB enhancement

[George Nassas]

Hi, just reviving this thread I started a while ago about my effort to  
switch mythvideo to use storage groups. I'm mostly sending an update  
for Anduin but in case anyone else cares...

I have scanning, browsing and playback working with storage groups.  
There's still some backfill to get some of the setup bits converted  
and whatever else I may have missed but it's largely there. Originally  
I figured I'd post a patch towards the end of this month but with the  
QT4 switch maybe I'll wait until that settles down. I'm way back in  
the svn 15800s so either way there's probably a bit of effort to bring  
the code up to head.

Anyway, the other thing I wanted to cover is if it might be worthwhile  
to handle removable media through some sort of dedicated storage group  
and scan them the same as everything else. I don't really use those  
devices so I'm not sure about the pros and cons.

- George