Early morning classes not supported

[psvenk]

Split off from #82. Some ROTC classes, like NS.100 (whose schedule is W6.30-8.30), begin before 08:00. These were previously misidentified as evening classes but are now excluded from Hydrant (also relevant: #27). Adding support for times outside of the [08:00, 22:30] range would require overhauling the timeslots system that Hydrant currently uses.