Update BubbleMat.hpp and BubbleMat.cpp
Return false in BubbleMat, if no penetration.
Fix and enable DEM-PFV-check.py.
Replace L3eom by SCgeom in stl and gts examples.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	pkg/dem/BubbleMat.cpp
	pkg/dem/BubbleMat.hpp