PVRChannelsOSD: add PreviousChannelGroup/NextChannelGroup actions handling
PVRChannelsOSD: remove hardcoded left/right navigation
[confluence] PVRChannelsOSD: use recently added Previous/NextChannelGroup actions
Merge pull request #2246 from pieh/channelosd

PVRChannelsOSD: replace hardcoded left/right group switching with proper action handling