Have point2dem record nodata value.
Have point2dem record nodata value.

Added nodata ... which is the same as default_value, but it's more
consistent with the rest of our tools.

When the user provides a nodata value and the output format is TIF, we
include the nodata metadata information.

oleg-alexandrov/StereoPipeline,ScottMcMichael/StereoPipeline,oleg-alexandrov/StereoPipeline,NeoGeographyToolkit/StereoPipeline,NeoGeographyToolkit/StereoPipeline,DougFirErickson/StereoPipeline,njwilson23/StereoPipeline,aaronknister/StereoPipeline,aaronknister/StereoPipeline,oleg-alexandrov/StereoPipeline,aaronknister/StereoPipeline,DougFirErickson/StereoPipeline,njwilson23/StereoPipeline,NeoGeographyToolkit/StereoPipeline,ScottMcMichael/StereoPipeline,DougFirErickson/StereoPipeline,oleg-alexandrov/StereoPipeline,njwilson23/StereoPipeline,NeoGeographyToolkit/StereoPipeline,njwilson23/StereoPipeline,aaronknister/StereoPipeline,NeoGeographyToolkit/StereoPipeline,oleg-alexandrov/StereoPipeline,njwilson23/StereoPipeline,aaronknister/StereoPipeline,ScottMcMichael/StereoPipeline,DougFirErickson/StereoPipeline,ScottMcMichael/StereoPipeline,NeoGeographyToolkit/StereoPipeline,DougFirErickson/StereoPipeline,oleg-alexandrov/StereoPipeline,ScottMcMichael/StereoPipeline,njwilson23/StereoPipeline,ScottMcMichael/StereoPipeline,DougFirErickson/StereoPipeline