[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 void parameter yields a 28 warnings with vs2013, e.g.,
```
Warning	183	warning C4002: too many actual parameters for macro 'GetCurrentTime' (..\..\xbmc\addons\AddonCallbacksPVR.cpp)	d:\code\xbmc-git\xbmc\epg\EpgInfoTag.h	476
```