start to curved edge geometry...  Edges render, but positioning is off.....

@MDCox As you can see, things are pretty close, but not ready to be merged:

![image](https://cloud.githubusercontent.com/assets/1875033/4464079/b40b0b68-48d0-11e4-8bad-ef923c4cb758.png)

Feel free to pull down this branch, make fixes, and submit a new PR with your fixes.