<ticket>#590</ticket>
<ticket>#590</ticket>

Added a refresh button to the packages configuration window

gui/preferences.py:
- QPackagesWidget:
  Added "Refresh Lists" button

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