Changes

* An attempt at better handling MS Windows not releasing the file handle on time in the test suite. The system and unit tests tearDown() method should now be resilient to the strange MS Windows behaviour of not releasing the relax state files. The tearDown() method should now complete even when this error occurs. A delay of 3 seconds has been added when the WindowsError occurs to give the OS some time before attempting to delete the file again. If this fails, then the file deletion operation is skipped.

* Better handling of temporary file and directory removal in the relax test suite. The new test_suite.clean_up.deletion() function has been created from the recent method of the same name. This is used by the tearDown() method of the system, unit, and GUI tests. It should prevent rare MS Windows errors from appearing due to the OS not releasing a temporary file after a close() call.