relax SVN archive

Converted all of the generic system/functional tests to the new unittest framework.

Converted all of the angle system/functional tests to the new unittest framework.

Converted all of the diffusion tensor system/functional tests to the new unittest framework.

Converted all of the model-free system/functional tests to the new unittest framework.

Converted the CSA and bond length value setting test to the new system test framework.

Converted the Bond length value setting test to the new system test framework.

Converted the CSA value setting test to the new framework.

Bug fix for the new system/functional test framework.

Now all tests from all TestCase instances are run.

Started to convert the model-free system tests to the new unittest framework.

The relaxation data reading test has been converted, but no other tests are currently functional.

Clean up of the operation of the --unit-tests and --system-tests command line options.

These now use the Test_suite_runner methods so that the 'relax' file need not deal with the
implementation details of the various test suite categories.