Add Shutdown Hook to close resources

[GoogleCodeExporter]

Add shutdown hook in Launcher to initiate plugin shutdown (unplug()).
This is a place to unload/close resources.

Original issue reported on code.google.com by vladimir...@gmail.com on 28 Dec 2013 at 12:24

[GoogleCodeExporter]

Update the Plugin Interface to include an unplug() (counter to plug()).  That 
method will be called during the closing of the Plugin's life cycle.

Original comment by vladimir...@gmail.com on 16 Jan 2014 at 12:39

• Changed state: Started

[GoogleCodeExporter]

Original comment by vladimir...@gmail.com on 15 Feb 2014 at 5:30

• Changed state: Done