Parallel test runs - thanks!

Hi A few people were able to use the new run-tests.php code to run tests in parallel on different platforms. I've plotted the results here: http://zoah.co.uk/update-parallel-run-tests-php. Thanks very much for doing that, thanks also for the bugs you found in doing so (blush) - I will fix. Interesting data, suggests that 4 processes is optimal and that the best we can hope for is being able to run in about 1/3rd of the time they run in at the moment. At some stage I will look at where it's spending its time and see if we can improve on these results. For now I think completing the implementation and fixing bugs has a higher priority for me. Zoe