relax SVN archive

Added a simple docstring to the relax_io module.

Fix for the renaming of io.py to relax_io.py.

The module renaming has been taken into account as well as the eventual removal of the IO class and
the conversion from class methods to module functions.

Added some comments for the import statements.

The open_read_file function is now imported as well.

Modified the unit tests for generic_fns.state to import from relax_io.

The function open_write_file is now imported (although it doesn't currently exist).

Renamed the relax io module to relax_io as it clashes with the Python io module.

Removed the old State class from the namespace of 'self.relax.generic'.

Change of the internal structure of the generic_fns.state module.

The State class has been eliminated and its methods load() and save() have been converted to module
functions.

Added a unit test for the generic_fns.state.save() function.

Added the framework for implementing unit tests for the generic_fns.state module.