or raises the existing
      singleton*.

      H = VMT_GISExportTool_GUI returns the handle to a new VMT_GISExportTool_GUI or the handle to
      the existing singleton*.

      VMT_GISExportTool_GUI('CALLBACK',hObject,eventData,handles,...) calls the local
      function named CALLBACK in VMT_GISExportTool_GUI.M with the given input arguments.

      VMT_GISExportTool_GUI('Property','Value',...) creates a new VMT_GISExportTool_GUI or raises the
      existing singleton*.  Starting from the left, property 