Execution with callback instead of looping

[pelshoff]

Hi Mike,

I took the liberty of adding callback signals instead of looping. This makes the first finishing child process call the parent to start a new process rather than waiting for the next process to finish. It took me a while to figure out that I needed to declare ticks (see http://nl3.php.net/manual/en/function.pcntl-signal.php, example 1) but on my quadcore processor the example I added runs in 5 seconds in stead of 8. I hope this helps and I am curious about any feedback you have for me.

Pim