Issue #9: Reminders

As a new user I want to be reminded of things. Pearl would say remember
to do this once. Maybe with a confirmation. It would not have a start or
end time.

- Add Reminder django model
- Add Reminder django admin
- Add Reminder tastypie resource
- Add Reminder backbone model
- Add Reminder backbone collection
- Add Reminder backbone view
- Add Reminder backbone template
- Add Reminder backbone edit view
- Reminder tests
- Drag reminder
- Announce reminders
- Create new reminder or event interface
- Fix for reminders not returning correctly
- Save rrule information
- Format reminder time template
- Update reminders when the day changes