Handle interrupts and display current test results

[Seldaek]

Sometimes on large test suites I get unexpected failures and after seeing a few I am thinking "ok what's up?" and don't really feel like waiting for the whole test suite to complete. Hitting ctrl-C, adding --stop-on-failure and rerunning potentially means a bunch of waiting too though..

So I was thinking, if ctrl-C would be caught by PHPUnit and it would render the current test results it collected, that would be really neat!

I am not entirely sure how it'd play with tests potentially triggering SIGINT themselves and such.. it might need to be made optional because of that.