Dev: Make travis stop on failure so errors are shown

.travis.yml

@@ -64,4 +64,4 @@ before_script:
     - java -jar selenium-server-standalone-3.7.1.jar -enablePassThrough false > /dev/null 2> /dev/null &
 
 script:
-    - DOMAIN=localhost phpunit
+    - DOMAIN=localhost phpunit --stop-on-failure # Stop so we can see errors.