Debug_Logging: Output debug information to the page or a log file

This class can be used to output debug information to the page or a log file.

It can output several types of event activity and show the current date and time, the user session, the calling function and line, as well a custom message.

The debug output can be displayed in the current page, or outputted to a file .

The size of the log files may be limited. When a log file exceeds the limit, the class can rotate the logs by renaming the current log file and creating a new one.