[mythtv-cmyth] Make/Break EPG broadcast UID

New functions to encode and decode program key in broadcast UID.
- MakeBroadcastID(): Encode self-relative timecode / channelID.
- BreakBroadcastID(): Decode self-relative timecode / channelID to find program at time.

Break broadcast id will run only with XBMC PR#3828. Else EPG hook data is empty and the message "No broadcast found" will be displayed.
[mythtv-cmyth] EPG menu hook to manage special recording rules

Manage "Not recording" rules with PVR timer screen:
- Enable menu hook setting "Show/Hide not recording rules"

Create special recording rules:
- Add EPG menu hook "Record all showings (this channel)"
- Add EPG menu hook "Record this showing every week"
- Add EPG menu hook "Record this showing every day"
- Add EPG menu hook "Record one showing (all channels)"
- Add EPG menu hook "Record new episodes (this channel)"