relax SVN archive

Alphabetical reordering of functions.

Function renaming and argument order changes in the maths_fns.rotation_matrix module.

The naming scheme is now more logical (as well as the argument order).

Added another unit test for maths_fns.rotation_matrix.R_axis_angle().

Bug fix for R_to_axis_angle().

All vector elements were NaN when the angle is 0. Now the zero vector is not normalised by zero.

Added a unit test for maths_fns.rotation_matrix.R_to_axis_angle() using R = I.

Created 3 unit tests of the maths_fns.rotation_matrix.R_axis_angle() function.

These are almost identical to those of quaternion_to_R().

Created 3 unit tests of the maths_fns.rotation_matrix.quaternion_to_R() function.

Fix to the frame order system tests.

This corresponds to the fixes in R_euler_zyz() where the rotation matrices were in the left-handed
universe and hence the rotation was back to front.

Fixes for the test_func3() and test_func4() unit tests.

The rotations were backwards because of the R_euler_zyz() fix!

Bug fix for the R_to_euler_zyz() function.

This matches the important bug fix in the R_euler_zyz() function.