Update .travis.yml

Author: bupy7

.travis.yml

@@ -1,11 +1,15 @@
 language: php
-
+dist: trusty
 php:
-  - 5.4
-  - 5.5
-  - 5.6
-  - 7.0
-
-install: composer install --dev
+  - '5.4'
+  - '5.5'
+  - '5.6'
+  - '7.0'
+  - '7.1'
+  - hhvm
+  
+before_script:
+  - composer install --no-interaction
 
-after_script: php vendor/bin/coveralls
+after_script:
+  - vendor/bin/coveralls -v