[mythtv] Channel matching for mythweb listings

[Chris Petersen]

> 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.

Didn't see it - I tend to skip over things that don't have interesting
subjects lines or contain mythweb/nuvexport (those get filed separately
so I don't miss them).

Anyway, I just committed a change to group channel listings by
callsign.  I don't have multiple lineups, so I have no idea to know how
this will affect scheduling, etc.  Please let me know if this
does/doesn't work.

-Chris