Blender Git Loki

Fix T47257: bevel crash when there are internal faces.

Bevel had assumed that when rebuilding a face that touches
a vertex with beveled edges, the edges of the face at that vertex
would be adjacent in internal order. That is not necessarily true
if there are edges with more than two faces attached.
We could just prohibit beveling any edges that touch a vertex
where this happens (we already don't bevel non-manifold edges)
but the use case in the model of T47257 seems reasonable.
Also had to fix the edge-ordering code, and the face reconstruction
code to take care of cases where the face normal may not be as expected.