Default is_abstraction flag in controller.
Default is_abstraction flag in controller.

vistrails/core/vistrail/controller.py:
  - VistrailController.__init__: default is_abstraction to False

celiafish/VisTrails,VisTrails/VisTrails,minesense/VisTrails,Nikea/VisTrails,minesense/VisTrails,minesense/VisTrails,Nikea/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,celiafish/VisTrails,hjanime/VisTrails,hjanime/VisTrails,Nikea/VisTrails,celiafish/VisTrails,minesense/VisTrails,hjanime/VisTrails,Nikea/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails