Update ResultPrinter to match PHPUnit changes

Signature changed in:
https://github.com/sebastianbergmann/phpunit/commit/052a1ccf7152c94a585f9399badcc9c0c507f8b3#diff-346100e9bdc9072e22f6b5976e629a7bL217
Merge pull request #12 from cognifloyd/patch-1

Update ResultPrinter to match PHPUnit changes