relax SVN archive

Added the relaxation curve fitting module to the __init__.__all__ array.

Added a stub of the function get_specific_fn() to specific_fns/__init__.py.

The function generic_fns.value.set() now calls this instead.

Shifted the Specific_setup class into the __init__ module.

This class will be replaced by the specific_setup() function but has been kept here for reference.

Big bug fixes.

The structures 'self.relax.specific' and 'self.relax.specific_setup' no longer exist!

Shifted all the specific_fns class imports and initialisations from main.py to __init__.py.

Converted the set() class method into a module function.

Implemented the spin_id unit test for the value.set() user function.

Implemented the param unit test for the value.set() user function.

Bug fix.

The value argment to the value.set() user function has been changed to 'val'. The argument was
clashing with the modules because the names were the same.

Implemented the val unit test for the value.set() user function.