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

safari/ext/popup.js

+// 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.
+with (safari.extension.globalPage.contentWindow)
+{
+  this.ext = ext;
+  this.TabMap = TabMap;
+}