KML Superoverlay driver cannot handle Folders

[pphunor]

The driver does not recognize the Region and GroundOverlay entries placed under a Folder node. See ​https://developers.google.com/kml/documentation/kmlreference#folder.

• An example KML can be downloaded from here (84MB): ​https://onedrive.live.com/redir?resid=E2CC0A25F3CEB4B7!106&authkey=!AO_hm98MiSO7Yq4&ithint=file%2czip
• An example mapfile layer using that KML:

  	LAYER
  		NAME "PROVA1"
  		TYPE RASTER
  		STATUS ON
  		DEBUG ON
  		DATA "prova1_mosaic.kml"
  		PROJECTION
  			"init=EPSG:4326"
  		END
  		CLASS
  			NAME "Superoverlay"
  			STYLE
  			END
  		END
  	END
  
  

I debugged and modified the driver so that it can handle the attached KML. I've chosen the solution with the least amount of changes, and it is not proved against any standards. Use it up if you think so.

[Even Rouault]

Thanks for the patch. I gave it a quick try, but it breaks opening the ​https://svn.osgeo.org/gdal/trunk/autotest/gdrivers/data/kmlimage.kmz which is used in the regression test. Could you correct it so that it still works with it ?

[Even Rouault]

Ah and please use 4 spaces instead of tabulation character as indentation.

[Even Rouault]

I came up with a different solution :

trunk r33283 "KMLSuperOverlay: recognize datasets that have a intermediate <Folder> that forms a <Document><Folder><Region/><GroundOverlay/> structure (#6343)"