Modified example to use WebGL.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk@2441 822214bb-dcf7-4c8d-a767-17ae0fb20d88
Added logic to ensure that the draw context's frame time stamp differs between frames.

git-svn-id: http://worldwind31.arc.nasa.gov/svn/trunk@2442 822214bb-dcf7-4c8d-a767-17ae0fb20d88