Update .travis.yml

Author: barryvdh

.travis.yml

@@ -3,19 +3,17 @@ language: php
 sudo: false
 
 php:
-  - 5.3
   - 5.4
   - 5.5
   - 5.6
   - 7.0
-  - hhvm
+  - 7.1
 
 matrix:
-  allow_failures:
-    - php: 7.0
   include:
     - php: 5.3
       env: 'COMPOSER_FLAGS="--prefer-stable --prefer-lowest"'
+      dist: precise
 
 before_script:
   - travis_retry composer self-update