Corrected "KeySnail" spelling and tidied more codes.
Moved in step with the add-on's behavior of clearing item.

Whether a finished item was cleared after open or show depends preferences of S3. Download Statusbar.
This plugin left these behavior to the add-on.
See also "extensions.s3downbar.function.removeOnOpen" and "extensions.s3downbar.function.removeOnShow".
Updated "s3dlbsnail" to version 0.0.2.