Web interface debugger improvement

If debug_web_interface is set in /etc/collorg/<db_name> config file,
(replaces former trace attribute) all the templates composing a page
are squared by a thick red border. When the mouse hovers the template,
a title is displayed showing the class name, the function name an the
execution duration.
Warning. It brokes the CSS an you may have to play with the overflow
property in some cases (for example to see Post.w3edit).