Pass the import url over to the standalone on /connector/saveItems.

Should address some issues related to translating via a proxy like this one
https://forums.zotero.org/discussion/63057/zotero-not-downloading-pdfs

Addresses zotero/zotero-connectors#3

chrome/content/zotero/xpcom/connector/connector.js

@@ -256,6 +256,9 @@ Zotero.Connector = new function() {
 					data.detailedCookies = cookieHeader.substr(1);
 				}
 				
+				// Cookie URI needed to set up the cookie sandbox on standalone
+				data.uri = tab.url;
+				
 				self.callMethod("saveItems", data, callback, tab);
 			});
 			return;