[Xui-interest] System tray support added

[Luan O'C. <lu...@xo...>]

Support for the system tray or launch area has been added. When a system 
tray icon is added the application can choose to stay resident in memory 
after the main window has been closed by setting the "ExitOnClose" 
startup property to false. The advantage of doing this is that the data 
model does not need to be reinitialized if the main window is just being 
redisplayed. This initialization can be significantly quicker than 
normal startup as all
the classes needed by the JVM are already loaded. If remote data is used 
the startup gain may be even greater as network access may not be required.

The tray icon provides two menu items, one to open the window and the 
second to close the window and exit the JVM.

This version of the class uses the SwingLabs version of the tray support 
and is therefore limited to Swing. If JDK 6 or later is being used then 
the JVM's tray support could be used for non Swing applications.

The system tray/stay resident option may be particularly valuable when 
used in conjunction with an embedded webserver, as a remote server could 
thereby signal the application to wake up and display new data or alerts 
as when such data becomes available by simply making a request to the 
client application's server. The same process could also be used to 
provide a tighter integration between a web page/web application and a 
XUI application.