relax SVN archive

Converted the get_data() function to the new relax design.

Converted the determine_graph_type() function to the new relax design.

Converted the Grace class methods into module functions.

Modified the set_error() base class method to accept the spin container.

Modified the sim_return_param() base class method to accept the spin container.

Modified the sim_return_selected() base class method to accept the spin container.

Created the sim_return_chi2() base class method.

Changed model_loop() to return the spin container.

Activated the model_loop() generator method.

Created the specific base class method model_loop().

This defaults to one model per spin system, and can be used by most analysis types.