relax SVN archive

Scripts can now be run again under Python versions 2.4 or lower.

Fix for the initialisation of the Bruker_import class.

This allows this module to be loaded in Python 2.4.

The runpy module is only imported if it exists.

Added a check for the runpy module.

Fix for the back_calc_I C function so that it works under Python 2.5.

Added wrapper methods to the relaxation curve-fitting specific code for the new C modules.

These allow the parameter numpy array from minfx to be converted into a Python list prior to sending
it into the C module.

Removed numpy from the relaxation curve-fitting C module code.

This now expects Python lists as arguments. This should help with incompatibilities between
different Python versions, as this seems to be due to the numpy C interface. See for example
the thread started by Min-Kyu <min-kyu dott cho att vanderbilt dot edu>
https://mail.gna.org/public/relax-users/2011-02/msg00000.html (Message-id:
<001f01cbd24f$350042d0$9f00c870$@cho@...>).

Decreased the accuracy of the PDC reading system test, as the PDC data is not accurate to 7 places.

The R1 value and error are now being read directly from the PDC file.

Fix for the PDC reading system tests, the data now matches the new PDC files.