pvr: Only shows specific actions for current category or 'ALL'

Avoid to show unusable specific actions for the current context.
paplayer: do not hijack main thread for pre-buffering streams
Merge pull request #2992 from FernetMenta/paplayer

paplayer: do not hijack main thread for pre-buffering streams
Merge pull request #2963 from janbar/pvr_update

pvr: Only shows specific actions for current category or 'ALL'