relax SVN archive

Removed an unused import.

Corrected the copyright header.

Copied 'specific_fns/relax_fit.py' to 'specific_fns/relax_disp.py' and commented most lines.

Commented lines will need to be tailored after the system tests code is completed.

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...

Removed some unused imports.

Added a directory and a script for relaxation dispersion curve fitting system tests.

The next step will be to find published data to use in the tests. We will need data for the three
cases of slow-, intermediate-, and fast-exchange...

Started the implementation of the relaxation dispersion code.

The first step was to introduce the framework for system tests.

Removed an unused import.

Corrected a small typo in the development chapter of the manual.

Created a branch for the implementation of the relaxation dispersion code.

This follows a thread started by Seb at:
https://mail.gna.org/public/relax-devel/2008-12/msg00058.html
(Message-id: <4951148F.9050105@...>)

and continued by Ed at:
https://mail.gna.org/public/relax-devel/2009-01/msg00003.html
(Message-id: <7f080ed10901060854v3e0c1ac6idb8fad319e43c7de@...>)