Fix slice positioning along curve
Fix slice positioning along curve

In orthogonal slice positioning mode based on curve node, slice position and orientation was completely off.

Slice spin around normal was specified with a relative angle, which did not result in reproducible slice positioning.
Instead, rely on the Parallel Transport reference frame, its minimal torsion along the curve, and initial orientation based on anatomical axis direction.

vmtk/SlicerExtension-VMTK