Blender Git Loki

- readded Subsurf "optimal" edge drawing/rendering
- added ME_EDGERENDER flag, barely changes things atm except makes
sure plain meshes with FasterDraw/etc set still render all edges.
The edge drawing system needs a bit of a revamping - it is a cool
feature but could use several improvements:
(1) The algorithm could be better in choosing the best edges to
draw.
(2) The drawflags should interact well with modifiers. It is wierd
to have a large grid with a deformer that draws no edges because
flags are only calculated based on base mesh.
(3) Drawflags should not be destroyed by editmode. Better design
would be a "Draw % of edges" button.

Of course, could also be the feature is not worth it and we
should just drop. Feel free to comment if you have an opinion.