ENH: WIP - Add .h5 formated transform storage of BSplines. See 0003788

Partial implementation for reading itkBSplineTransform (for ITKv4)

Mostly implemented but the transform that gets read in is identity
and not the one in the file. Probably something wrong with
this cast:

• typedef itk::BSplineTransform< T,VTKDimension,BSPLINE_TRANSFORM_ORDER > BSplineTransformType;
• typename BSplineTransformType::Pointer bsplineItk =
• dynamic_cast< BSplineTransformType* >( warpTransformItk.GetPointer() );

The transformation itself is not populated with correct data,
so need to reach inside to get spacing, origin, etc.

From: Steve Pieper <pieper@bwh.harvard.edu>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23574 3bd1e089-480b-0410-8dfb-8563597acbee