Clean code to take advantage of new L5.5 features, bring back some dusk

tests now we can use headless chrome.

Squashed commit of the following:

commit d32d6e9dca7eb26303435c738f7c547e5009b86b
Author: Jonny Barnes <jonny@jonnybarnes.uk>
Date:   Wed Sep 6 14:43:52 2017 +0100

    Add dusk tests, cleanup other parts of travis.yml

commit 7633b407ee222a3f4a222f889f23acf4b5549c22
Author: Jonny Barnes <jonny@jonnybarnes.uk>
Date:   Wed Sep 6 14:38:39 2017 +0100

    I think dusk works locally with headless chrome now, just struggling on my slow laptop

commit fcbc83bb0a53ac046c1af09e8caf296799a940ef
Author: Jonny Barnes <jonny@jonnybarnes.uk>
Date:   Tue Sep 5 15:47:39 2017 +0100

    Get latest package versions and remove un-needed service provider entries

config/app.php

@@ -206,41 +206,11 @@ return [
         App\Providers\EventServiceProvider::class,
         App\Providers\RouteServiceProvider::class,
 
-        /*
-         * Laravel Debugbar
-         */
-        Barryvdh\Debugbar\ServiceProvider::class,
-
         /*
          * Thujohn’s Twitter API client
          */
         Thujohn\Twitter\TwitterServiceProvider::class,
 
-        /*
-         * Phaza’s Postgis library
-         */
-        Phaza\LaravelPostgis\DatabaseServiceProvider::class,
-
-        /*
-         * Laravel scout
-         */
-        Laravel\Scout\ScoutServiceProvider::class,
-
-        /*
-         * Postgres Engine for Scout
-         */
-        ScoutEngines\Postgres\PostgresEngineServiceProvider::class,
-
-        /*
-         * Laravel Tinker
-         */
-        Laravel\Tinker\TinkerServiceProvider::class,
-
-        /*
-         * Eolquent Sluggable
-         */
-        Cviebrock\EloquentSluggable\ServiceProvider::class,
-
     ],
 
     /*