relax SVN archive

The relax data store to_xml() method now can add all data pipes to the XML file (or a subset).

The results.write() method now asks to_xml() for just the current pipe to be stored, whereas
state.save() supplies no 'pipes' argument to have all pipes stored.

The save_state() function now calls the relax data store to_xml() method.

This method is currently only for one data pipe, and is used by the results writing user function.

Added the pickle flag to save_state().

This defaults to True to prevent relax failures during the XML file implementation.

Redesign of the relax state loading for adding support for a XML formatted state file.

Half of the load_state() is now in load_pickle(), and a new function load_xml() added.
The determine_format() function will tell if the file is a pickle or XML file, and then
load_pickle() will run the appropriate loading function.

A few fixes for the test_write_read_pipes() system test.

Shifted the test_write_read_pipes() system test to the 'state' test module.

The program state is now being saved as the results file is for just one data pipe.

Updated the specific_fns module __all__ list for the SRLS module.

Added a very basic, and completely empty module and class for SRLS analysis.

This is to allow the data pipe to be created.

Removed an empty line.

Deleted the __init__() class methods as these were empty, and shifted the docstring to that of the class.