created files for start and stop URL's

extension/data/start_urls.txt

+https://www.google.com/
+https://www.bing.com/

extension/data/stop_urls.txt

+https://en.wikipedia.org/wiki/Main_Page

extension/js/background.js

@@ -2,7 +2,7 @@ var debug = 1;
 var start_time = Date.now();
 var stop_time;
 var duration;
-var urls_to_compare = readTextFile("../data/urls.txt");
+var urls_to_compare = readTextFile("../data/stop_urls.txt");
 
 /* this code base courtesty of https://stackoverflow.com/questions/14446447/javascript-read-local-text-file#14446538*/