relax SVN archive

Created the get_instance() function to return the appropriate class instance.

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

Fixed the specific_fns docstring. It should be at the top and it is a package not a module.

Added a docstring for the specific_fns module.

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.