#13 Only show parts of time grid which contain class time

[Keith Lea]

If a schedule only has class from 10AM to 4PM, the
Scheduler does not need to show from 6AM-10AM and from
4PM-11PM. Perhaps showing 8AM to 6PM would be appropriate.

To make browsing possible schedules simpler, the time
grid should be sized to fit all possible schedules, so
the range of the grid does not change for each schedule.