Add textured line overlay rendering.
Change terrain height calculations to be triangulation-dependent for
improved accuracy.
Add triangulation-dependent terrain normal function.
Support separate S/T wrap modes for textures.
Rename CVector2D_Maths since it no longer conflicts with simulation
CVector2D.
Coalesce freed chunks in vertex buffers, to avoid excessive
fragmentation.
Add some things to help debug vertex buffer allocation a little.
This was SVN commit r9929.
