Update Placemark objects altitude mode in Examples and Tutorials

[zglueck]

Description

Many of the instances of Placemarks being used in the Examples and Tutorials rely on the default WorldWind.ABSOLUTE altitude mode. In some viewing positions, placemarks may appear below the terrain.

Steps to Reproduce

1. Zoom in and out of the MIL-STD-2525 Placemarks example

Expected behavior: [What you expect to happen]

Placemark'a associated with terrain should appear referenced to the terrain.

Actual behavior: [What actually happens]

Placemark's associated with terrain sometimes reference the ellipsoid.

Reproduces how often: [What percentage of the time does it reproduce?]

Always

Operating System and Version

n/a