[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()