Top level KML object for the kdm-idl kdm_kml group. A kdm_kml
object holds a kdm_kml_object. This object contains the generic
code that all other inherited KML objects might use
kml = obj_new( 'kdm_kml', filename='output.kml' )
saveKML: Write the KML to disk
KMLhead, KMLbody, KMLtail: Produce the head, body, and tail KML code
Written by: Ken Mankoff, July 2009.