Bug 1023662 - [User story] Show 5 day week view r=gaye

**WIP**, still going to clean up the code and try to use external templates for most of the elements.. I have a few more changes locally (trying to abstract it better so that we can use same logic for day view as well), but will probably take another full day to clean up the code..

I'll rebase this later and squash commits.
this function is only executed when the calendar visibility changes, so it should not really matter. the timeController cache should update even if the calendar is disabled. when we re-enable the calendar it will fire an `add` event for all the cached busytimes.