[mythtv-cmyth] Manage special recording rules

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

New functions to make and break a broadcast UID for program

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)"