- Add option to compute sin with Bhaskaras approx instead of using a LUT.
- ADD THIS!!! Rendering could be made faster by reusing the mapped vertex
  coordinates between iterations when processing triangles: this supposes that
  a triangle that's being rendered quite likely shares 1 or 2 vertices with the
  previously rendered triangle, so there is no need to expensively transform and
  screen-map all its vertices! ALSO: create a function that optimizes the model
  for rendering, i.e. rearranges the triangle order to favor this optimization!