Glacial update for non-vertical rays

These commits fix a number of issues and introduce the calculation of effective splitting for non-vertical rays. Specifically they:

* Merge various development branches together
* Fix a bug in the way we call MS_plot that stopped the generation of pole figures
* Fix a bug in the approach to the calculation of isotropic velocity
* Split the Vs and Vp plots to make the differences more visible
* Handle the two formats of EBSD data we now have
* Deal with non-vertical rays in the calculation of effective splitting