adding hhvm support to travis testing
adding hhvm support to travis testing

stof/csv,Teino1978-Corp/Teino1978-Corp-csv,postalservice14/csv,Perlkonig/grav-plugin-table-importer,hmcclungiii/csv-1,vlakarados/csv,HeyRatFans/csv,thephpleague/csv,mortenhauberg/csv