Update filtered outputs *only* at the end of model "tick"

Do not update them immediately. They are strongly connected to the
tick history, which also isn't updated immediately after property
change, but only at the end of model "tick".

The fact that Filtered Outputs were updated immediately, but at the
same time they were following tick history operations (eg. push,
invalidate) was causing that samples were added (=> property update),
then removed (=> tick history invalidation), then added again (=> tick
history push).
Update Filtered Output tests due to its new behavior

If you take a look at removed comments, you can see that now there is
no conflict between filtered outputs' values during simulation and
during moving through history states. Everything is more consistent.