Add support for thin plate spine transformations

This could be based on the implementation in [Stephan Schlager's](https://github.com/zarquon42b/) [Morpho](https://github.com/zarquon42b/Morpho) package. Alternatives include ITK or the java implementation [jitk-tps](https://github.com/saalfeldlab/jitk-tps) from the saalfeldlab / [John Bogovic](https://github.com/bogovicj).
