relax SVN archive

Added a system test to check that relax save files cannot be loaded as results files.

Updated some test data for the unit tests.

Last fix for bug #17361 (https://gna.org/bugs/index.php?17361) the loading 1.2.x sim data.

The frequency information is now correctly updated when data is missing.

Completed the test_read_results_1_2_pse() model-free system test for reading relax 1.2.x results.

Bug fix for the relaxation data add_data_to_spin() function - missing data was not properly eliminated.

For the 1.2 results files, the model information is now being setup even if None.

Another fix for bug #17361 (https://gna.org/bugs/index.php?17361) the loading 1.2.x sim data.

This time the global structures were too large - the lists were being appended to for each spin and
simulation, rather than only each simulation.

Fix for bug #17361 (https://gna.org/bugs/index.php?17361).

The chi2_sim structure should have been initialised to a list, not a dictionary.

Added a system test for reading relax 1.2.x version results files.

This is from Sebastian Morin's PSE-4 data, truncated, and is to catch the bug of not being able to
handle simulations.

Error messages are displayed for all the 'Execute relax' buttons when the execution lock is set.