relax SVN archive

Improvements to the STDOUT and STDERR handling in the _RelaxTestResult class.

Now STDOUT and STDERR are stored simultaneously within the same StringIO() instance so that the
streams are merged into one. This means that the test suite tests print out the messages as they
would appear on screen.

Renamed the prompt.unselect module to prompt.deselect.

Big spelling fix! Renamed all references to 'unselect' to 'deselect'.

Fix for the mean_and_error() method.

The spin container was being referred to as 'data' rather than 'spin'.

Added some missing imports and fixed an incorrectly named function call.

Converted the mean_and_error() method to the new relax design.

Updated the assign_function() method to the new relax design.

Updated the relaxation curve fitting system test script to call spin.name().

Simplified the name() and number() functions. They now handle complex spin selections.

Fixed the call to generic_fns.spin.name().