HighResolutionTerrain improvements. Added interface on ElevationModel to control extreme-values caching.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk/WorldWind@2014 822214bb-dcf7-4c8d-a767-17ae0fb20d88
Added null check in GDALUtils.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk/WorldWind@2023 822214bb-dcf7-4c8d-a767-17ae0fb20d88
Modified interface to Globe and ElevationModel to accept an array of targer resolutions to their getElevations methods. Modified HighResolutionTerrain to use that interface.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk/WorldWind@2024 822214bb-dcf7-4c8d-a767-17ae0fb20d88
Do not use pick frustum to determine if KML region content is active. Culling against the pick frustum prevents the user from interacting with content (such as an open balloon) that exceeds the region's bounding box. See WWJ-231 and WWJ-388.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk/WorldWind@2029 822214bb-dcf7-4c8d-a767-17ae0fb20d88
Commented out code forcing a file URL in PointPlacemark. It prevents jar file URLs.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk/WorldWind@2030 822214bb-dcf7-4c8d-a767-17ae0fb20d88