Daily planning things to consider: Show finished events in daily planning as read-only

@piotr.gawron you will find this interesting.

As you know, daily planning columns (workers) are sort by availability, but, when you browse past days, you might find some inconsistencies, with workers with less availability shown before others with more apparent availability.

The thing is, cancelled, finished etc visits do not appear in the daily planning, but they are considered for the calculus of this availability percentage that is then used. Is not a major issue but, maybe we should consider either show old events, or modify the way the calculation is done.

Also, I found some inconsistencies like: An appointment type link for one worker and subject, and another one, for the same day but different hour with different worker but same subject. This is:

subject - worker1 - same day 10:00 subject - worker2 - same day 12:00

But then, if you go to subject visit and appointments you will only found one of those. I thought that maybe the appointment was reschedule but the appointment type links weren't removed. Is that possible?