Fix schedules that cross midnight

When schedules cross midnight, they have scheduled times greater than
1440 so just remove these and put them at the top of the list of events
Handle a personal weather station being down

Personal weather stations can go down and, when they do, the
sprinkler_pi weather adjustment returns an adjustment of 0%.  Change
this to return 100% if the personal weather station has not returned an
update within the last hour.