Event Type Labels Should Be Clickable

[cycomachead]

Clicking should filter the list of events ?event_type=x in the URL.

Follow up enhancements:

• give text filtering event types
• show which event type is filtered
• allow selecting multiple event types?
• if so, have a reset button.

TBD: Refactor schedules controller to have a general filtering interface? How does this interfere with 'my schedule'