Change findAllByProject -> findAllByProjectId

Maintain consistency and be explicit about what we're finding.
Scope like variable

Just for safety.
Implement RSVP's for Events

This feature allows users to toggle their RSVP response
to a specific event.

/event/attend/:id registers that you want to attend event :id
/event/cancel/:id cancels your registration for event :id
/event/rsvp/:id returns true/false as to whether you're registered
/event/rsvp/ returns all the event rsvps for this user
/event/[find/]:id returns all the events for a given projectId, which
  includes an `rsvps` field with userIds for all users that have
  rsvp'd and an `rsvp` field which is whether the logged in user
  has rsvp'd.
/event/ical/ returns the user's ical object
/event/ical/:id returns the ical object for projectId :id
findAllByProjectId now includes rsvps
Add test for user's iCal

Generate ical for user; fix bug in not calling `done` in sync fn