relax SVN archive

Python 3 support for Modelfree4 and Dasha.

The subprocess.Popen class works with byte arrays rather than strings in Python 3+. The Python
objects are now interconverted when the Python 3 encode() and decode() methods are detected.

Removed the pickle format information and arguments from the state user function definitions.

Eliminated the State.test_state_pickle() system test as pickled states are no longer supported.

Removed the ability to save and restore states using the pickle module.

A pickled state is of no use to relax anymore. It's removal is needed for Python 3 support. So now
everything defaults to the XML formatted output.

Python 3 fix - removed the use of the string module from generic_fns.spectrum.

Fix for the Relax_fit.test_bug_12670_12679() system test for the changes to Grace files at r17716.

Python 3 fix for the relax_io.open_write_file() function.

This now matches the behaviour of open_read_file() in that there are three different behaviours for
opening bz2 and gz files for writing to for the different Python versions (one for Python 2, one for
Python 3.0 to 3.2, and one for Python 3.3+). All byte streams have been eliminated as
open_write_file() is for creating text files.

Python 3 fix for the Noe.test_noe_analysis() system test for the grace.write precision changes.

For consistency between Python 2 and 3, the grace.write user function outputs to 15 decimal places.

This increased precision will only be of use in the relax test suite.

Python 3 fix for the Pipes.test_pipe_bundle() system test.

The order of bundle names returned by generic_fns.pipes.bundle_names() is not guaranteed in Python 3.