Contribute classes copied from IRTK/image++ to MIRTK/Image module

Some of the IRTK image module classes you use were not refactored for the MIRTK before as they had not been used in any of my registration code. When we now, however, have a module that depends on these old IRTK classes, I would prefer having (refactored) versions of these in the MIRTK Image module.
