CalendarItemFilter Part 1

[louietyj]

Completely untested code. Does the code make sense?

We need separate filters for Tasks and Events unless we return a List which will be messy. So the controller will need to do four steps:

1. getFilterTokenDefinitions, and use it to tokenize input
2. parseIsTaskEvent, and use it to decide whether to process tasks / events / both
3. Process tasks using filterTasks
4. Process events using filterEvents

Reason for so many steps is that if step 3 or 4 go wrong, controller's renderDisambiguation needs a lot of contextual information to do anything sensible. (1) allows the controller to populate the natural dates, and (2) allows the controller to autocomplete "task" or "event".

[coveralls]

Coverage decreased (-0.7%) to 51.491% when pulling 4cb7cbe on filter-concern into 44f205a on master.

[irvinlim]

Looks good! Though we still need to test it.