[mythtv] Channel change speed

[jasonmiller at micron.com]

> From: Reza Naima [mailto:reza at reza.net]
> 
> would it be possible to _not_ tear down the ringbuffer and just issue the 
> change channel command instead.  perhaps jump to just before the head of 
> the ringbuffer before changing the channel.  It just means you can back up 
> the view something on the previous channel...

Which would actually be a nice feature that I think may have been requested 
before.  If you know the football game is about to start on another channel 
but want to finish watching Trading Spaces which happens to be playing live 
15min delayed, just change channels, the osd pops up and shows the channel 
change but trading spaces keeps on truckin' then blips over to the beginning 
of the football game in progress when it ends.  Kinda neat :)