[mythtv] mythvideo DB enhancement

[George Nassas]

Hi, just an update for Anduin and anyone else who cares.

I finished off most of my changes in June and have been running it  
without any obvious issues so I'm going to move forward from the  
February svn I'm using to current source. Weekends are my only time  
for coding and during the summer I have other things going on so, you  
know, it might take a little bit. I also want to see the mythvid-ui  
branch to merge back into trunk.

A couple of questions:

- the database convert was the hairiest part and I found it convenient  
to unwind by throwing errors. There don't seem to be many (any) try/ 
catch blocks in the rest of myth. Is there some restriction I don't  
know about?

- I reassigned the contents of videometadata.filename to be a relative  
path but that's going to cause heartburn to mythweb and the uPnP code.  
Instead, I could leave that column as-is and make a new filepath  
column for the relative path. We could have .filename update with each  
scan and users would have to know to do one after they mess around  
with file placements within storage groups. It sounds like Chris is  
heading in that direction for recordings too.

Longer term I think the database-related code should be pushed into a  
common library so that uPnP & mythweb don't have to reinvent the  
wheel. The video plugin then becomes a UI-only component. I could take  
that on after this is done although at the speed I produce code...

- George