Possibly fix weird aspect ratios on some camera changes.
New shadow map positioning and sizing code to allow zooming out to get decent range of shadows.
float version of Tile.GetElevation moved to Tiles.GetElevation so that tile edge wrapping can work.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@247 a9f3cfff-6c41-7446-b0ca-052bd761e6eb