Adiciona botão de voltar a controlador painel

sapl/templates/painel/controlador.html

@@ -21,4 +21,8 @@ FECHADO
     <input type="submit" name="stop-painel" value="Fechar Painel" class="button primary">
     <input type="submit" name="save-painel" value="Salvar" class="button primary">
 </form>
+</br>
+</br>
+<a class="btn btn-primary" href="{{request.META.HTTP_REFERER}}">Voltar</a>
+
 {% endblock %}