provide zid in js so we can use it from client

boot.php

@@ -990,7 +990,8 @@ class App {
 			'$icon' => head_get_icon(),
 			'$head_css' => head_get_css(),
 			'$head_js' => head_get_js(),
-			'$js_strings' => js_strings()
+			'$js_strings' => js_strings(),
+			'$zid' => get_my_address(), 
 		)) . $this->page['htmlhead'];
 	}
 

view/tpl/head.tpl

@@ -23,6 +23,7 @@
 
 	var updateInterval = {{$update_interval}};
 	var localUser = {{if $local_user}}{{$local_user}}{{else}}false{{/if}};
+	var zid = {{if $zid}}'{{$zid}}'{{else}}null{{/if}};
 
 </script>