Further enhancements and bug fixes to pvr.nextpvr addon

- added dialog to set recurring recordings, including recurrence type, padding, number of recordings to keep, and recording directory
- added support for EDL 
- added support for retrieving and storing last playback position
- now requires NextPVR 3.1.1 or higher
- fixed a bug that could cause an EPG event with no description to have a copy of last show's description, or cause a crash if the user was unlucky.
- more flexible approach to genre