Blender Git Loki

Getting rid of setlinestyle: add imm_draw_circle_wire_dashed() util.

Needed a bit of twisting in generic private func behind the imm_draw_circle
helpers, but think it's fine.

Note that this demonstrate yet another downside of new dashed shader
compared to olde line style: not only does it needs more complex setup,
and can only work with PRIM_LINES type of primitives, but it also
behaves totally wrong with chained short segments!

We really need to find a better way to do this effect at some point. :(