Updated travis.yml to use PHPunit defined in composer.
Updated travis.yml to use PHPunit defined in composer.

mattclegg/puphpet,artetecha/puphpet,mattclegg/puphpet,artetecha/puphpet,thedeedawg/puphpet,mattclegg/puphpet,thedeedawg/puphpet,thedeedawg/puphpet,ikari7789/puphpet,ikari7789/puphpet,ikari7789/puphpet,artetecha/puphpet,artetecha/puphpet,ikari7789/puphpet,mattclegg/puphpet,thedeedawg/puphpet,mattclegg/puphpet,ikari7789/puphpet,thedeedawg/puphpet,artetecha/puphpet