use full space on small devices (#310)

* use full space on small devices

I often use my smartphone for quick actions and always was annoyed of this wasted space.

* hide card-image on small devices

esphomeyaml/dashboard/templates/index.html

@@ -47,9 +47,9 @@ <h5>Select Upload Port</h5>
 <div class="container">
   {% for i, entry in enumerate(entries) %}
   <div class="row">
-    <div class="col s8 offset-s2 m10 offset-m1 l12">
+    <div class="col s12 m10 offset-m1 l12">
       <div class="card horizontal">
-        <div class="card-image center-align">
+        <div class="card-image center-align hide-on-small-only">
           <i class="material-icons very-large icon-grey">memory</i>
         </div>
         <div class="card-stacked">