Add vim tagline.

src/operations/operation.delete.tmpl.html

@@ -1,3 +1,4 @@
+<!-- vim: set tw=80 ts=2 sw=2 sts=2: -->
 <div class="modal top am-fade" tabindex="-1" role="dialog" aria-hidden="true">
   <div class="modal-dialog">
     <div class="modal-content">