relax SVN archive

Switched the theta and phi angles in cartesian_to_spherical() to match the rest of relax.

Created a new module for performing coordinate transformations.

The new function cartesian_to_spherical() has been added as the first conversion.

Fixed another typo in populate_2nd_eigenframe_iso_cone().

Fixed a typo in populate_2nd_eigenframe_iso_cone().

Bug fixes for populate_2nd_eigenframe_iso_cone() as the frame order equations were incorrect.

Bug fix for compile_2nd_matrix_pseudo_ellipse_free_rotor() - element 04 was incorrectly set.

It was set to 11 rather than 00.

Fix for the pseudo-ellipse frame order system test.

The chi2 is different with the corrected equations.

Simplification of compile_2nd_matrix_pseudo_ellipse() by removal of identical numerical integrations.

A number of the frame order matrix diagonal elements are equal to each other, so the repetitive
calculations were removed for speed.

Fix for compile_2nd_matrix_pseudo_ellipse(), the pseudo-ellipse has slight asymmetry in daeg.

Fixes for the free rotor pseudo-elliptic frame order matrix equations.

The previous equations were plain wrong!