new merge of #78 (Use Symfony's ProcessBuilder to safely build phpunit command.)

This is a merge and fix of the pr #78  which adds  Symfonys ProcessBuilder to both runners.
I somehow failed to keep the contributor record from the original commits :(

The main fix is in the bin/phpunit-wrapper. I decided to use a split by regular expression just to keep the changes as small as possible because passing the arguments as an array would mean to split the logic of WrapperRunner and Runner out of the ExecutableTest.

Would like to hear some thoughts on this ;)