Popout inbox

Rather than opening the inbox in its own window, let it appear as a
browser action popup by default, but allow promotion to its own window
if requested.

js/background.js

@@ -67,8 +67,6 @@
             });
         });
 
-        extension.browserAction(window.openInbox);
-
         // refresh views
         var views = extension.windows.getViews();
         for (var i = 0; i < views.length; ++i) {