[mythtv] Support for multiple input sources

[Isaac Richards]

So, I've been working on this a bit..  I've made most of the database changes 
as outlined here:

 http://www.snowman.net/pipermail/mythtv-dev/2002-August/000205.html

and wrote a little setup program (console only, and tv_grab_na only, for now).  
I've got the epg working properly, the TV OSD working properly, and most 
everything else working with the changes..  Kinda broke the displayed channel 
numbers for already recorded programs in the playback/delete dialogs, and 
upgrading will blow away people's single and timeslot scheduled recordings, 
but I figure that's all ok.

So, with all this, it finally shows the proper channel information on screen 
if you're using a non-tuner based input, like a satellite receiver. (assuming 
you can change channels with a command line app, of course).

Only thing left to do is update the scheduler to deal with all this..  Has 
anyone out there written a scheduler like that before, or seen code to do it?  
Just need to deal with X physical cards with Y inputs per card and Z sources 
of channel information, it's not complicated in the slightest. =)

Nothing's been committed to CVS yet, though.

Isaac