relax SVN archive

The PCS centre position can now be a numpy array.

The PCS centre can now be forcefully overwritten.

The arg_check.is_num_list() now will allow numpy arrays.

The atomic position can now be directly supplied to pcs.centre().

Fix for the R_to_euler_zyx() function.

The beta = 0 problem point does not exist!

Modified the check_return_conversion() method to print out more information for debugging.

Wrote all the test_R_to_euler_ijk() unit tests to cover all Euler angle conventions.

Converted all the R_to_euler_zyz() unit tests into one.

This will simplify the setup of the unit tests for the other Euler angle conventions.

Added all the 12 Euler angle notations to the rotation matrix module.

The methods added include:
axis_angle_to_euler_ijk(),
euler_ijk_to_axis_angle(),
euler_ijk_to_R(),
R_to_euler_ijk(),
reverse_euler_ijk().

Bug fix for the calc_rotation() function.

The axis permutation for | Azz | >= | Ayy | >= | Axx | is now correctly performed.