improve inset code by not allocating an array the size of edges - instead count all inset edges and allocate an array only for those.
also fixes an error where edge lengths were being compared while the verts were being placed. (now do beforehand)
- Even option (like solidify even option)
- Relative option (insets based on lengths of surrounding edges)
TODO: merge tares when 2+ face corners meet but don't form a contiguous region.
