relax SVN archive

Deleted the now useless add_data_to_spin() function.

Spacing fix.

Removal of the test_labels() function, as this was only needed with the old design.

Simplified the return_data_desc() function.

Updates for a number of model-free system tests for the changed relax_data.read() user function.

Simplification of the return_value() function.

The model-free code no longer calls the deleted relax_data.data_init() function.

Updated the relax_data.read() back end for the new ID string based design.

The update_data_structures_pipe() and data_init() functions have been deleted and the pack_data()
function highly modified.

Modified the value.set() user function GUI element so that the parameter element is an input field.

Redesigned the relax_data.read() user function front end for handling data ID strings.