<ticket>#194</ticket>
<ticket>#194</ticket>

Making sure to remove duplicate aliases when pasting modules to a pipeline.
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gui/vistrail_controller.py
   VistrailController.paste_modules_and_connections()
       added function remove_duplicate_aliases() that is called soon after
       the pipeline is unserialized. The function will remove aliases from the
       pasted modules that are already present in the current pipeline.

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