new interpolation scheme!

- in wip_Felix.m, the last section after %NEW CODE! will demonstrate the
new interpolation
- rotation and translation are interpolated at the same time (H-Matrix
is interpolated)
- read_TrackingFusion_files now looks very different and still has 1 or
2 things that have to be checked, but i think it is better now. If it
creates trouble, revert this single file in the git shell.