Show contributor/contribution details on mobile

Refs #163

On small screens, when selecting a contribution or contributor, the
lists are hidden and only the details are shown.

app/templates/dashboard/contributions/show.hbs

@@ -42,7 +42,7 @@
           kredits will be issued.
         </p>
         <p>
-          {{link-to "Re-submit contribution …" "contributions.resubmit" model class="button small green"}}.
+          {{link-to "Re-submit contribution …" "contributions.resubmit" model class="button small green"}}
         </p>
       </div>
     {{/if}}
@@ -50,7 +50,7 @@
 
   <div class="actions">
     <p>
-      {{link-to "Copy & edit as new" "contributions.resubmit" model class="button small"}}.
+      {{link-to "Copy & edit as new" "contributions.resubmit" model class="button small"}}
       {{#if model.ipfsHash}}
         <a href="{{ipfsGatewayUrl}}/{{model.ipfsHash}}"
            class="button small" target="_blank" rel="noopener">