travis: PHP 7.0 nightly added

`--dev` is by default for almost a year

Author: Tomáš Votruba

.travis.yml

@@ -4,16 +4,19 @@ php:
   - 5.4
   - 5.5
   - 5.6
+  - 7.0
   - hhvm
 
 matrix:
+    fast_finish: true
     allow_failures:
+        - php: 7.0
         - php: hhvm
 
 before_script:
   - composer self-update
-  - composer install --dev --prefer-source --no-interaction
+  - composer install --prefer-source --no-interaction
   - phpenv rehash
 
 script:
-  - phpunit --coverage-text
+  - phpunit --coverage-text