Make galleries responsive

templates/shortcodes/gallery.html

 <section class="section gallery">
-  <div class="columns is-multiline is-same-height is-centered is-mobile">
+  <div class="columns is-multiline is-same-height is-centered">
     {% for picture in page.extra.gallery[name] %}
-      <div class="column is-one-third is-half-mobile">
+      <div class="column is-one-third">
         <a href="#">
           <figure class="image is-4by3">
             {% set image = resize_image(path="@/" ~ page.colocated_path ~ "/" ~ picture.image, width=800, height=600) -%}