Updated travis.yml

Author: GrahamCampbell

.travis.yml

@@ -1,11 +1,16 @@
 language: php
 
 before_script:
-    - composer install --prefer-source
+  - composer self-update
+  - composer install --no-interaction --prefer-source --dev
 
 php:
-  - 5.4
+  - 5.3.3
   - 5.3
+  - 5.4
+  - 5.5
+  - 5.6
+  - hhvm
 
 notifications:
   email: false