Feature: Turn filter item, or even entire filter conditions into custom attributes. #547
Description
When interactively slicing a dataset (applying more and more conditions to isolate a particular situation), it could be that one would suddenly want to compare the case you're zoomed in on against all cases that don't satisfy that condition.
For individual filter items, the user may "reverse" the filter type (include vs exclude, between vs not between etc), but this would still only let the user "switch", and only on a per filter item basis.
If the user could somehow turn the filter item, or the entire filter axis, into an attribute, then they could see the entire dataset divided into those cases that satisfy the condition vs the ones that don't (or perhaps it would be more appropriate to evaluate it so it can be divided into true/false/null)