BUG: Call itk.down_cast on ProcessObject outputs in functional call
BUG: Call itk.down_cast on ProcessObject outputs in functional call

For functional Python ProcessObject or Filter calls, call itk.down_cast
on outputs to return the most derived type.

BRAINSia/ITK,malaterre/ITK,vfonov/ITK,malaterre/ITK,richardbeare/ITK,Kitware/ITK,hjmjohnson/ITK,malaterre/ITK,hjmjohnson/ITK,hjmjohnson/ITK,vfonov/ITK,LucasGandel/ITK,Kitware/ITK,LucasGandel/ITK,LucasGandel/ITK,malaterre/ITK,malaterre/ITK,Kitware/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,hjmjohnson/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,Kitware/ITK,hjmjohnson/ITK,vfonov/ITK,BRAINSia/ITK,LucasGandel/ITK,vfonov/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,thewtex/ITK,BRAINSia/ITK,vfonov/ITK,InsightSoftwareConsortium/ITK,vfonov/ITK,Kitware/ITK,Kitware/ITK,richardbeare/ITK,thewtex/ITK,thewtex/ITK,thewtex/ITK,vfonov/ITK,malaterre/ITK,BRAINSia/ITK,richardbeare/ITK,thewtex/ITK,LucasGandel/ITK,richardbeare/ITK,vfonov/ITK,thewtex/ITK,richardbeare/ITK,vfonov/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,LucasGandel/ITK,LucasGandel/ITK,malaterre/ITK,malaterre/ITK,BRAINSia/ITK,hjmjohnson/ITK