Improves a lot the edges computation algorithm
Improves a lot the edges computation algorithm

stephomi/sculptgl,beni55/sculptgl,beni55/sculptgl,ytiurin/sculptgl,anteaterho/sculptgl,anteaterho/sculptgl,stephomi/sculptgl,grimor/sculptgl,nonconforme/sculptgl,ytiurin/sculptgl,grimor/sculptgl,nonconforme/sculptgl