relax SVN archive

Entire classes of system tests can now executed.

Rather than running the entire system test suite or individual tests, the system tests can now be
run by class. For example to execute all of the N-state model system tests, just type:

$ relax -s N_state_model

The prompt and script UI self._execute_uf() method can now properly handle non-keyword args.

Uncommented some code which was commented out for debugging purposes.

This should not have been committed!

Basic fixes for the GUI test base _execute_uf() method, including removal of the dir arg.

Eliminated the self._test_dir test class variable.

The system and GUI tests will now use the same script path.

Removed the recently added GUI test 'scripts' directory.

The GUI tests will from now on use the system test scripts directly (after they have been modified
to use self._execute_uf() for executing the user functions).

Modified and renamed the self._execute_uf() method so that it will work with the system test scripts.

The file and directory arguments are now merged, as required by the GUI user function pages.

Converted the bmrb_rw.py system test script to use the new prompt self._execute_uf() method.

The GUI test framework will need slight modification to use this script directly still.

Created a special private method for the prompt/script UIs for executing user functions.

This self._execute_uf() method will be used for the sharing of scripts in the system and GUI tests.

Refactored the system and GUI tests for code sharing.

The GUI tests now can inherit tests from the system tests. This is done for the BMRB system tests,
both of which now run as GUI tests. For this, a test class specific script_exec() method has been
added. For the system tests, it passes the system tests script into the interpreter. For the GUI
tests, it executes the script using the function locals so that the GUI test execute_uf() method is
accessible.