click on the map to add points to the track
drag points to move them
click on points to put comments,the point then becomes a 'Point of Interest'
     4 types of comments:
     - HTML Bubble : info bubble displayed on the map, above the point
     - HTML Content : HTML that will be displayed on the side of the map
     - Image url : url of an image to be displayed on the side of the map. URLs should start with http://
     - Page url : url of a page to be displayed on the side of the map, within an iframe.
modified points are in 'blue'. You have to click on the 'save' button to store the data to the server.
clean reload will discard the modification and reload the track.