A vtkSmartPointer<vtkUnsignedCharArray> was being assigned a raw
vtkUnsignedCharArray pointer, resulting in a leak. Changed assignment
to take a smart pointer instead.

Took the opportunity to make some raw pointers smart pointers instead,
making the implementation more consistent.

Also removed some debugging output that was left in.

Change-Id: I03693d0545f1c34969a868a48e5821671c10aebc