Split test

Test polygon classification and splitting.

Test the the coplanarity of spacial identity pretty hard by cloning everything in jaws and asserting that the results are coplanar.

Checks out `poly_split_poly` `poly_classify_vertex` and `poly_classify_poly` as well as `clone_f3` and `clone_poly` 

**Edit**

And I removed travis because they're not worth the effort to get going at the moment. Patches welcome :crying_cat_face: