changed weblaf in pom to weblaf-core and weblaf-ui, updated to 1.28 and
fixed AbstractFileFilter import which changed
Fixes #144: Added cancel button on every progress bar, it is now
possible to cancel every single calculation; but after abortion of
calculation the flags are not set correctly so that the
lattice/implications are not recalculated after tab switch, you need to
change context back and forth to set the flags again
See #156: changed description of csv, oal, cxt to reflect that only the
context is saved
Abortion of clarification and reduction now correctly noticed in state