[BUGFIX] *Quadrangulate* was giving bad results when groups were empty

Author: lkruel

otls/sop_quadrangulate.hda/INDEX__SECTION

@@ -10,5 +10,5 @@ Inputs:       1 to 1
 Subnet:       true
 Python:       false
 Empty:        false
-Modified:     Fri Oct 11 10:36:34 2019
+Modified:     Mon Nov  4 15:38:05 2019