Made the bubble use the ext object from the background page instead of including ext/background.js

safari/ext/popup.js

 (function()
 {
   // Safari will load the popover once, and then show it everytime the icon is
   // clicked. While Chrome loads it everytime you click the icon. So in order to
   // force the same behavior in Safari, we are going to reload the page of the
   // bubble everytime it is shown.
   safari.application.addEventListener("popover", function()
   {
     document.documentElement.style.display = "none";
     document.location.reload();
   }, true);
 
   // import ext into the javascript context of the popover. This code might fail,
   // when the background page isn't ready yet. So it is important to put it below
   // the reloading code above.
   var backgroundPage = safari.extension.globalPage.contentWindow;
-  ext = backgroundPage.ext;
-  TabMap = backgroundPage.TabMap;
+  window.ext = backgroundPage.ext;
+  window.TabMap = backgroundPage.TabMap;
 })();