Support recording groups

[LockeCJ]

I make use of recording groups in MythTV in order to separate my recordings, my wife's, my daughter's, and those shared by all of us. Unfortunately, MAF doesn't seem to be aware of these and displays all of the recordings. This is quite a bit to scroll through.

I would like to see this implemented in two ways. First, I'd like to be able to set a default recording group, much like a standard frontend is able to. When initially loading the recordings, the default group's recordings should only be visible. Second, I'd like to be able to easily switch recording groups.

[billmeek]

Added enhancement label.