1/ rename to "url" - those do not have to be only our urls, we can reference external things, there is no "url" collision with our shipped 3rd party libs

2/ add new style of wwwroot relative urls "|course/view.php" - I hate typing $CFG->wwwroot over and over again, it would distinguish nicely from true relative links

3/ there are some attempts to make url comparisons in our code - I doubt it works with relative urls, we can either make the comparing more clever or make the absolute urls already in constructor