BUG: Fix memory leak in SlicerDICOM2FullBrainTractographyModuleGenericTest

This commit sets the parent for the workflow. Doing so will ensure the
workflow and its children will be deleted.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23711 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Reference parent when creating DICOM2FullBrainTractography workflow

Prior to this commit, the layout was incorrectly used as a the parent
widget. This was working because the function "QLayout::layout()" return
the layout that would be otherwise returned by "parent.layout().

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23712 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: DICOM2FullBrainTractography now supports setting a new scene.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23713 3bd1e089-480b-0410-8dfb-8563597acbee