Added HHVM to travis.yml
Added HHVM to travis.yml

mikeSimonson/DoctrineBundle,nicolas-grekas/DoctrineBundle,mikeSimonson/DoctrineBundle,skafandri/DoctrineBundle,OskarStark/DoctrineBundle,hacfi/DoctrineBundle,skafandri/DoctrineBundle,gencer/DoctrineBundle,Soullivaneuh/DoctrineBundle,nicolas-grekas/DoctrineBundle,Soullivaneuh/DoctrineBundle,fervo/DoctrineBundle,chrisguitarguy/DoctrineBundle,gencer/DoctrineBundle,hason/DoctrineBundle,OskarStark/DoctrineBundle,javiereguiluz/DoctrineBundle,fabpot/DoctrineBundle,dunglas/DoctrineBundle,fabpot/DoctrineBundle,hason/DoctrineBundle,chrisguitarguy/DoctrineBundle,hacfi/DoctrineBundle,doctrine/DoctrineBundle,fervo/DoctrineBundle,javiereguiluz/DoctrineBundle