Rewrote events/index

Split the action into five actions: index (which shows upcoming events), past (paginated view which shows all old events), incomplete (which shows all events not marked as completed, cancelled or declined), month (which shows all events in a given month) and search (which shows all events that match a search query).

Removed events/calendar_full and events/mobile because they never worked.

Also removed events/lost because since it is not longer possible to create an event without an eventdate, it is no longer needed.

refs #82