WGetAgent: Download files using the wget program

This class can download files from remote sites using the wget program usually available on Linux/Unix systems.

The class can call the wget program to start the download of a file into a given directory. Optionally it may limit the download rate.

When the download is started, the class can call an given method of another class to pass the download session details like the session identifier, destination and url.

Each download session can be logged to a individual file that may be removed when the download is finished.

When the download is finished, the class may execute a given program or shell script.