Add testing against newer PHP versions

Author: tomphp

.travis.yml

@@ -5,3 +5,11 @@ script: php vendor/bin/phpunit; php vendor/bin/behat --format progress
 php:
   - 5.4
   - 5.5
+  - 5.6
+  - 7.0
+
+matrix:
+    fast_finish: true
+    allow_failures:
+        - php: hhvm
+        - php: 7