Blur buttons on submitting a zephyrgram.

This way the user can continue using the keyboard to navigate
after sending a message, without pressing additional keys.

(imported from commit 014997194f546fe56da063e19d3818e949a3ee7e)

zephyr/static/js/zephyr.js

@@ -54,6 +54,7 @@ $(function() {
                        .text('Sending')
                        .stop(true).fadeTo(0,1);
             buttons.attr('disabled', 'disabled');
+            buttons.blur()
         },
         success: function (resp, statusText, xhr, form) {
             form.find('textarea').val('');