dashboard: add title to index-vm box's buttons

circle/dashboard/templates/dashboard/index-vm.html

@@ -3,8 +3,10 @@
   <div class="panel-heading">
     <div class="pull-right toolbar">
       <div class="btn-group">
-        <a href="#index-graph-view" data-index-box="vm" class="btn btn-default btn-xs"><i class="fa fa-dashboard"></i></a>
-        <a href="#index-list-view" data-index-box="vm" class="btn btn-default btn-xs disabled"><i class="fa fa-list"></i></a>
+        <a href="#index-graph-view" data-index-box="vm" class="btn
+            btn-default btn-xs" title="{% trans "summary view" %}"><i class="fa fa-dashboard"></i></a>
+        <a href="#index-list-view" data-index-box="vm" class="btn
+            btn-default btn-xs disabled" title="{% trans "list view" %}"><i class="fa fa-list"></i></a>
       </div>
       <span class="btn btn-default btn-xs infobtn" title="{% trans "List of your current virtual machines. Favourited ones are ahead of others." %}"><i class="fa fa-info-circle"></i></span>
     </div>