Moved all terrain code out of BSScene and into new BSTerrainManager.
Added logic to manage multiple terrains for mega-regions.
Added new functions to BulletSimAPI to match the library.
Moved all of the terrain creation and setup logic from C++ code to C# code.
The unused code has not yet been removed from either place. Soon.
Moved checks for avatar above ground and in bounds into BSCharacter.
Robert Adams