Bug fix for cone_pdb() for when no MC sims are run.
Fix for the N-state model arg checks.
Fixes for the negative cone.
Both the positive and negative cones are now made.
Bug fix for the R_to_axis_angle() function. The axis needs to be normalised.
Added the new function R_to_axis_angle().
The Euler angles are now wrapped between 0 and 2pi.
Missing import.
Partly reverted r9167 - the previous reversion.
The command used was: svn merge -r9167:9166 maths_fns/frame_order_models.py
Partly reverted r9167 - the previous revision.
The command used was: svn merge -r9167:9166 maths_fns/frame_order_matrix_ops.py
This returns the cone axis.