DOC: corrected definition of DTI affine transform



git-svn-id: https://svn.bigr.nl/elastix/trunkpublic@4357 4d348492-3962-11de-aa85-65a2020054a3
DOC: updating the manual


git-svn-id: https://svn.bigr.nl/elastix/trunkpublic@4358 4d348492-3962-11de-aa85-65a2020054a3