Mgv5 get ground level at point function. Fast spawn player version
Mgv5 1 up 1 down overgeneration for biome surface continuity
Optimise getTileInfo()

getTileInfo() ~1.5x faster
getSmoothLight ~2.0x faster
Optimise functions from CNodeDefManager and VoxelManipulator

CNodeDefManager::get()
VoxelManipulator::addArea()