relax SVN archive

Eliminated the model-free specific analysis API data_type() method.

This functionality is now provided by the parameter list object.

Eliminated the last of the specific analysis API return_units() methods.

This functionality is now provided by the parameter list object.

Added the PCS and RDC as parameters for the frame order and N-state model analyses.

These are now defined in the respective parameter list objects. The base method add_align_data()
has been created to avoid code duplication.

Large improvement for the lib.software.grace module.

The '*_err' and '*_bc' parameter names for the parameter error and back-calculated parameters
respectively are now supported. This allows these values to be easily plotted.

Removed the frame order API return_units() method.

This method has been superseded by the parameter list object.

Fixes for the units of the ave_pos_x, ave_pos_y, and ave_pos_z frame order parameters.

Replaced the frame order API model_type() method with the base _model_type_global() method.

The two methods were identical anyway.

Replaced the frame order specific API model_loop() method.

The base method _model_loop_single_global() is used instead.

Created the specific analysis API common method _is_spin_param_false().

This simply returns False. The is_spin_param() frame order method has been deleted and this common
method is now used instead.

The specific API PARAMS object is now private.

Apart from fixing a number of unit tests, these aliased singletons should not be accessed by the
rest of relax.