Events starting and stopping at the same time are considered as overlaps
Partially related to issue #104 but slightly different, because 104 is about "truly" overlapping events whereas this ticket here is about not-really-overlapping events.
The problem: if you have an event ending at 10h00 and an event starting at 10h00, they are considered as overlapping and therefore create multiple columns in a weekview's day, instead of considering that they are contiguous (as they are, from the user's point of view; anything with less than a few minutes of overlap is essentially contiguous) :