Load Layout

This option allows a user to load a previously saved data analysis graph
layout.  The layout consists only of node connections and positions
within the graph, and has no module specific configuration information
in it.  Layouts are useful if the same fundamental graph will be used
over and over, but the configuration is likely to vary from use to use.

When this option is selected, a file selection dialog will appear, with
the default layout directory as it's starting place.  Layouts are stored
in files, so the directory tree is traversed until the desired layout
file is found and selected.  Double clicking on the desired layout file
or pressing the OK button will cause the selected layout to be loaded.

Once a layout is loaded, the individual modules will have to be
configured, and then the system may be run.

