Committing ICE-VisIt functionality for viewing a set of SILO files, each
representing an individual time slice. This takes a set of SILO files
and creates a .visit file that contains the name of each file separated
by new line characters. The VisIt engine does the rest. Added the
ability for the individual SILO file names to be viewed as children of
the .visit file in the Visit File TreeViewer. Setup the hooks for those
children to clicked and used to add their own scalar plots in the VisIt
editor, but have not fully implemented it yet. 

Signed-off-by: Alex McCaskey <mccaskeyaj@ornl.gov>