WIP: change conversion between Euler and (versor,Affine) transforms

- How versor->Euler?
   Do this like versor->Affine (i.e. don't use rotation, use set/getMatrix)

- How Euler->versor?
   Do this like Affine->Versor (i.e. use utility function "orthogonalize"
       that convert rotation to versor).

- How Affine->Euler?
   Do this like Euler->Affine (i.e. use set/getMatrix)
WIP: comment out versorRigid3D as it is not used by BFitv4
WIP: editorial changes
WIP: replace centeredVersorTransInitializer with ordinary centeredTranInitializer
WIP: one line editrial change
WIP: change transform setup to be suitable for Euler3D in ResampleInPlace test