Load Session - Box filter deselection lost

[chrherold]

If a session is loaded the Boxfilters of 'area' Brightness average' and 'Deformation' are included as chosen even though they were deselected in the Session that was saved.

[chrherold]

Same thing happens on filter import

[paulmueller]

The problem was that these filters were set active by default in any case. I disabled this. By default, now no box filters are set and the user has to choose them explicitly. I think this is the better anyways. I think I just put them there for quick testing...