tests: added php 7 & hhvm-nightly to travis test matrix
tests: added php 7 & hhvm-nightly to travis test matrix

Mikulas/dbal,dyamon-cz/nextras-dbal,jasir/dbal,jasir/dbal,nextras/dbal,nextras/dbal,dyamon-cz/nextras-dbal,jasir/dbal,Mikulas/dbal,Mikulas/dbal,nextras/dbal,dyamon-cz/nextras-dbal