v1.2.1

Did some general cleanup, all code is identical to v1.2

Added two gnuplot scripts to plot the slowness surface, one with and one without plotting the group directions.

v1.2

Implemented a different way of calculating the pseudoinverse. This version will be much (~25%) faster than the previous ones in calculating enhancement factors, with no loss in accuracy.

v1.1: +set_enhancement_approx, minor bugfix

Added numerical scheme for calculating the enhancement factor set_enhancement_approx.

Minor bugfix in a faulty cartesian-to-spherical conversion in set_direction_cartesian.

v1.0

Merge branch 'master' of https://github.com/JanJaeken/christoffel