Add tests for d91a3269334fd70dee7fb2321dddd7994d2730c4
Add more flexible 12-hour time parsing

- 1am -> 01:00
- 12 PM -> 12:00
- 1:23p -> 13:23
Merge pull request #2 from CoCycle/parsing-time

Allow more flexible time input for groups, with non-standard times converted before validation.