Comment 2 for bug 897840

Implemented on branch ree-calendar-more-events-link.

Some remarks:

- this works identically both in the Staff, and the normal (narrow) calendars

- The More link is only shown if there are overflow events in that box, and it also displays how many events are hidden.

- The More link brings to the list view of the day. I found this will be better and more consistent solution for us on long term, than the original proposal of redirecting to the Calendar (non-list) view.

- Similarly to how this works in the month view, we can introduce similar links in the calendar UI whenever there is a possibility of overflowing events. (For example: in the day view, a slot can also fill up if there are many events contained by it, etc.)