Add PHP 5.5, 5.6 and HHVM to travis config
Add PHP 5.5, 5.6 and HHVM to travis config

salipro4ever/valitron,danielfpedro/valitron,mitschool/valitron,vlucas/valitron,zonuexe/valitron,asabirov/valitron,nadeka/valitron