[mythtv] NOTICE: XMLTV support changes

[Stuart Morgan]

I've added two patches to #1777, xmltv_capabilities_3.diff and 
programdata_changes.diff which I'd appreciate Datadirect and xmltv users 
testing. Both patches need to be installed, I've only kept them separate to 
simplify things on my end.

If you are running an old grabber don't upgrade first. It would be good to 
know that it handles them gracefully.

I expect there will be bugs or mistakes to discover. This isn't the final 
version, I've yet to do a final clean up and review.

P.S. This doesn't include the 'cache' capability support, which I've decided 
to delay for two reasons. 1) It isn't actually needed in 99% of cases. 2) It 
would complicate testing of the core changes.
-- 
Stuart Morgan