Locking PhantomJS installer to version 2.1.1 as it was causing issues - https://github.com/jonnnnyw/php-phantomjs/issues/97

composer.json

@@ -19,7 +19,7 @@
         "symfony/filesystem": "~2.3|~3.0",
         "symfony/yaml": "~2.3|~3.0",
         "twig/twig": "~1.16",
-        "jakoch/phantomjs-installer": "~2.1"
+        "jakoch/phantomjs-installer": "2.1.1"
     },
     "require-dev": {
         "phpunit/phpunit": "~4.0",