Switch to my own images, with dependencies satisfied

Necessary PHP modules, as well as Composer, are provided in the new images: https://git.ethitter.com/docker/images/container_registry.

.gitlab-ci.yml

@@ -30,8 +30,6 @@ PHPunit:PHP5.3:MySQL:
   script:
     - phpcs -n
     - phpunit
-  when: manual
-  allow_failure: true
 
 PHPunit:PHP5.6:MySQL:
   image: containers.ethitter.com:443/docker/images/php:5.6