pvr: improve handling in live tv gui

* tv/radio channels were merged into one list
* channel type switching (tv/radio)
* adds a new selection dialog for channel groups
pvr: adds action ACTION_PREVIOUS_CHANNELGROUP and
ACTION_NEXT_CHANNELGROUP
cosmetics: comments and whitespaces
pvr: adds label control for selected type of epg

This adds a new label control for output the guide type (timeline,
channel etc.), so that the group label control holds the channel group
name in epg view.
pvr: observe channel group changes in guide window
pvr: change control label for group selection to Group: [Name of group]
cosmetics: rename CONTROL_BTNCHANNEL_TYPE to CONTROL_BTNCHANNELS
pvr: adds message parameter to activate specific pvr window

This adds the ability to use built-in function ActivateWindow()
with addition [dir] parameter to open a specified pvr window.
Valid values: "tv", "radio", "guide", "recordings", "timers", "search"
pvr: use click instead of focus for controls
confluence: adds changes for live tv section
confluence: use new label control for output type of epg
confluence: prevents opening sidebar on init (set defaultcontrol to 50)
confluence: removes the labels of controls as they are set dynamicly
confluence: use ActivateWindow() to open pvr related windows