new Geometry.OCCSafeUnbind to disable fast unbind optimization (e.g. for tag backward compatibility): cf. #1928

enhance crack plugin

See merge request !468

# Conflicts:
#   CHANGELOG.txt

use brute-force calculation of bboxes if Geometry.OCCBoundsUseStl is set: OCC's algorithm enlarges the box by a factor that is hard to predict (combining STL deflection and shape tolerance). While this is safe, it's annoying for our use of bboxes. So let's simply compute the bounds of using the STL nodes and be done with it.

handle degenerate case when the same element touches both sides of the same crack with different nodes

only save groups of elements when saveGroupsOfElements is negavtive if the (dim+1)^th digit is 1 (as documented); this allows to use other values to disable group of element saving altogether

fix vertex->edge adjacency when reading msh (v4) files

See merge request !467