Modified Placemarks example to show how to use a 2525 tactical symbol as the placemark image. Added an example illustrating how to edit PointPlacemark labels when the user clicks on them.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk@2378 822214bb-dcf7-4c8d-a767-17ae0fb20d88
Added call to consume in placemark editing example.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk@2379 822214bb-dcf7-4c8d-a767-17ae0fb20d88
Added always-on-top flag to PointPlacemark.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk@2380 822214bb-dcf7-4c8d-a767-17ae0fb20d88