relax SVN archive

Wrote the __minimise_setup_pcs() method.

Modified the N_state_opt class to accept PCS data.

The __init__() docstring has been significantly expanded as well.

Converted minimise_setup_rdcs() and minimise_setup_tensors() into private methods.

Shifted the __update_model() method for fixing the alphabetical ordering of methods.

Fix for the __update_model() method.

This was only working if both RDC and PCS data are supplied.

A call is now made to assemble the PCS data necessary for optimisation.

Changed the way optimisation of the N-state model is set up.

This will allow multiple base data types to be used simultaneously.

Added a module docstring.

Fixed all the calls to __base_data_types() and subsequent use of the returned list.

Fixed __base_data_types() to properly identify tensors as the base data source.