More virtual globes enumeration

Norman Vine of osgPlanet sent me an email that included several (new to me) globes. I'll integrate them into our main list soon.

1) osgPlanet linked from http://www.ossim.org ( 2004 )
Norman Vine, Mark Lucas

2) Fledermaus http://www.ivs3d.com/products/fledermaus/fledermaus_pro.html (??)
Larry Mayer

3) FlightGear http://www.flightgear.org ( ~1995 )
Curt Olsen, Norman Vine

Primarily vector based but worthy of inclusion
4) Hipparchus http://www.geodyssey.com ( ~1990 )
Hrvoje Lukatella