Additional PHP version tests (php-master)

Author: buffcode

.travis.yml

@@ -1,12 +1,20 @@
 sudo: false
+
 language: php
+
 php:
   - 5.4
   - 5.5
   - 5.6
   - 7.0
+  - master
   - hhvm
 
+matrix:
+  fast_finish: true
+  allow_failures:
+    - php: master
+
 before_script:
   - cd tests
   - composer install -n