[mythtv] Channel matching for mythweb listings

[Bruce Markey]

Chris, you may have seen this on the user list but someone
pointed out that a recent enhancement to the EPG hasn't made
it's way into mythweb. That is, now that the scheduler can know
that channel 3 KVBC on digital cable is the same as channel
3 KVBC on analog, the EPG only lists channel 3 once as long as
the callsigns match. 

This is by no means a must fix for the release but a nice touch
you may want to look into when you have a chance.

--  bjm