[mythtv-cmyth] Cosmetics around time_t type

- time_t is undefined arithmetic type. In GetEPGForChannel(), convert startTime to number of minutes since epoch before cast.
- Check times of PVRTimer: If original values equal 0 (NULL), time() will return current time as expected.
- Fix timeslot for all.
[mythtv-cmyth] Force reload recordings an reconnect

Since commit d81b051f78028585dc43b5ed72872fd2ad0cabf4
Remove useless function MythEventHandlerPrivate::RecordingListChange()
[mythtv-cmyth] EPG Info:  Remove overlapping and fill gap

PVR update EPG entries to remove overlap and fill gap, updating start time of entries.
This is a problem for us to match entries with myth database using channel id and starttime.
So here i remove gap and overlapping before transfer entry, maintaining our start time.