Blender Git Loki

Fix T39184: Multisegment bevel profiles should curve in-plane sometimes.

When the multisegment profile joins two unbeveled edges, all in the same
plane, users desire that rather than the current behavior of linear
interpolation between those edges, the profile should curve.
This changes behavior to do that. The old behavior can be obtained
by setting the profile parameter to 0.25, if desired.