Whether or not to overwrite files.
If this property is set to true, existing files will be overwritten when decompressing. When Extract or ExtractAll is called, each file specified in Files will be checked for existence. If a file exists, the Overwrite event will be fired, and the files will be overwritten if OverwriteFiles is set to true.
More precise control of which files should be overwritten may be gained by listening to the Overwrite event and altering its parameters when the event is fired.