[PVR] Timeshifting: Fixed EpgInfoTag::[IsActive|WasActive|InTheFuture]

Changed EpgInfoTag::[IsActive|WasActive|InTheFuture] to take timeshifting into account. 
Fixes wrong event info shown at several places in kodi UI when timeshifting (e.g. Video OSD).
The whole PVR code base is littered with `void` parameters. I think it's required in C but not in C++ so they should just be removed.