Debug system : Output debug information to an HTML log

This class can be used to output debug information of the current script to an HTML log file.

It sets up the PHP error handler to a class function that generates HTML formatted output of the errors that may be triggered during the current script execution.

The class may also output arbitrary debugging messages also formatted as HTML. Optionally, the messages may include the current values of super-global variables.

The debug output may be displayed as the current script output or added to a given log file.