Closing vistrail did not work
Closing vistrail did not work

app.close_vistrail relied upon get_current_vistrail returning the view
being closed.  This is not the  case anymore so we  should now provide
the current controller instead.

gui/vistrails_window.py:
- QVistrailsWindow.close_vistrail:
  Need to include controller when calling app.close_vistrail, because
  the view is no longer guessed
- QVistrailsWindow.update_window_menu:
  Added check for current_view being None

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