fix size of asteroids and planets on nav, wasn't taking into account entity scaling
make entity draw is two directions, near to far and far to near.  this allows opaque geometry to be drawn starting at near plane and blended from the far
Render blended textures using depth buffer for culling but don't write to depth buffer.

This allows opaque geometry to block blending if it is in front and save pixel fill
rate. while letting multiple blended textures to stack.