Origin/wip/events and commitments quickfix

Want to merge fixes to Event, Commitment, EventTest, and CommitmentTest classes into dev:
- isValid* methods have been moved to a new ValidationUtil class in calendar.utils
- Overhauled Commitment to be based entirely on Event Class
- Commitment class once again throws exceptions
- Addressed failing commitment tests
- Added requirements to isValidName: cannot be default text, must contain alphanumeric character
- Removed requirement for the date of an event to be in the future