Copied 'prompt/relax_fit.py' to 'prompt/relax_disp.py' and commented lines which will need to be
tailored after the system tests code is completed.
Moreover, the directory for system tests data ('test_suite/shared_data/relax_disp') is now added,
although the 'svn add' command had been used before the last commit (r8229). Weird behavior, but,
anyway, the directory is present now...
