Added HHVM

Author: Nyholm

.travis.yml

@@ -1,8 +1,9 @@
 language: php
 php:
-  - "7.0"
-  - "5.6"
-  - "5.5"
+  - 7.0
+  - 5.6
+  - 5.5
+  - hhvm
 
 services:
   - phpredis-server
@@ -11,7 +12,7 @@ matrix:
   fast_finish: true
 
 before_install:
-    - phpenv config-rm xdebug.ini
+    - if [[ $TRAVIS_PHP_VERSION != 'hhvm' ]]; then phpenv config-rm xdebug.ini; fi;
     - pip install --user codecov
 
 before_script: