Add a panel containing tasklist to bottom screen

This is implemented as a separate process, since creating and running
toplevel windows from inside Metacity has issues.

We now grab a DBus name, and exec the child process.  The child monitors
our name to know when to exit.

svn path=/trunk/; revision=153

js/ui/main.js

@@ -98,8 +98,8 @@ Signals.addSignalMethods(ClutterFrameTicker.prototype);
 function start() {
     let global = Shell.Global.get();
     
-    // Here we grab our DBus name, etc.
-    global.late_init();
+    global.grab_dbus_service();
+    global.start_task_panel();
 
     Tweener.setFrameTicker(new ClutterFrameTicker());