Many fixes for the frame_order.permute_axes user function.
The z-axis inversion is now encoded into a 3D numpy array as the index of the new z-axis position
needs to be stored. The cone_theta_x, cone_theta_y and cone_sigma_max parameters are now permuted
in reverse 'perm' data structure by calling its index() method. And the cone_theta_x - cone_theta_y
to y-axis - x-axis switch has been removed (this may need to be reintroduced later).
