Removed testing against HHVM nightly (#66)

* Test against PHP 7.1 and not against HHVM nightly anymore

* Removed 7.1 to not overly bloat the test matrix

* Changed 7.0 back to 7 so the effective changes are only what the PR is about now

Author: WyriHaximus

.travis.yml

@@ -6,13 +6,11 @@ php:
   - 5.6
   - 7
   - hhvm
-  - hhvm-nightly
 
 matrix:
   allow_failures:
     - php: 7
     - php: hhvm
-    - php: hhvm-nightly
 
 before_script:
   - composer install --dev --prefer-source