Add basic support for multiple calendars

[phansch]

A new branch, since the old branch was kinda broken

What needs to be done:

Models/Controllers

• [x] Tests for calendar model (ALL the things, see models/event_spec for examples)
• [x] Tests for Event model (should always be part of calendar)
• [x] Make old tests pass
• [ ] Clean up unused files generated by scaffold
• [x] Unique URL token for each calendar
• [ ] Guest user

Views

• [x] List of calendars
• [x] Single calendar, accessed via token
• [ ] calendar#show should equal the old events#calendar
• [ ] calendar#new form
• [ ] calendar#edit form
• [ ] Integration tests for every view
• [ ] Move list of calendars into partial and include partial in calendar#show view
• [ ] Need unique token for each event as well

I also imagine there will be a lot of pain with merging it in :+1:

ref #16

[phansch]

Making progress!