relax SVN archive

Shifted the Python 2 and 3 compatibility module 'compat' into the relax library.

Improvements to the test_library_independence.py development script.

This script for checking the independence of the relax library will now recursively import all
packages and modules in the library and report at the end a list of all failures.

Removal of all unused imports in the lib.dispersion package.

Added a script for testing the independence of the relax library.

Removed the dependency on the relax dep_check module from the relax library.

This is to further decouple the library from relax.

Divide by zero avoidance fix for the rotor frame order model module lib.frame_order.rotor.

Improved support for printing stack tracebacks with RelaxWarnings.

The '--traceback' command line option will now show a full traceback. A replacement
warnings.showwarning() function has been written to write out the traceback before the
warnings.formatwarning() replacement function is called.

Decreased the amount of newlines around the printout from the '--error-state' command line option.

The lib.errors module is now really independent of relax - the compat module is no longer used.

Instead, the Python 2 and 3 versions of the pickle module are imported using try statements.

Reordered the debugging command line options and removed the '-r' shortcut.