Provides a way to get the screen size of the primary monitor, especially when
there are several being used.
exclude_taskbar: in, optional, boolean, default=0
Set this keyword to exclude the taskbar from the monitor size.
This keyword is ignored on all but Windows machines.
Dick Jackson, www.dick-jackson.com
Written, 8 March 2011. DJ
Modified to only use IDLsysMonitorInfo for IDL 6.3 and higher. 23 Feb 2012. DWF.
Copyright (c) 2011, Fanning Software Consulting, Inc.