relax SVN archive

Added the diffusion tensor data structure unit test 'test_set_prolate_params'.

This test checks that all the parameters, vectors, and matrices associated with the prolate
spheroidal diffusion tensor are set up correctly.

Added the '--unit-test' command line argument.

Supplying this argument to relax will cause solely the unit tests of the test suite to be run.

Changes to the output formatting functions of the test suite.

The methods 'self.heading()' and 'self.summary_line()' have been converted to functions and have
been shifted from the file 'test_suite/system_tests/main.py' into the new file
'test_suite/formatting.py'. The final printout by 'test_suite/runner.py' now used these functions.

Modification of the 'test_set_tm' diffusion tensor data structure unit test.

After setting the tm parameter, the automatically generated Diso parameter is tested to see if it is
correctly set.

Modified the 'test_set_Diso' unit test.

Rather than testing the RelaxError message string, the 'self.assertRaises()' function is called to
assert that a RelaxError must occur.

Modified the 'test_set_Diso' and 'test_set_tm' unit tests to use the proper assert functions.

Completed the 'test_set_Diso()' and 'test_set_tm()' unit tests.

Modified the system/functional + unit test running code so that only the true unit tests are run.

The current setup was looking for unit tests throughout the relax source tree and accidentally
running the code in the file 'minimise/line_search/test_functions.py'.

Spell check of the 'unit_test_runner' module.

Set the executable bit on the diffusion tensor data structure test module.