Another fix for a slightly different case from the original report, to give better orientation.
Vertex normals influence on the orientation is now scaled by the alignment with the cut direction.
Also use face normal instead of loop normal which can be unreliable when the corners edges are co-linear.
Custom-data on newly created face data was often rotated.
Now the API doesn't copy data from adjacent loops when creating faces.
Most functions were already overwriting this anyway.
Since such decisions are better made at a higher level, now it's the responsibility of the caller.
Certain shapes could trick the inside/outside test.
An edge between 2 planar faces could be selected for detecting face-flipping (which failed).
While this could be prevented by skipping those edges,
use a method which searches for the outer most face-loop, then check it faces the center.
Instead of offsetting along normals, smooth positions are now
calculated on a sphere defined by the vertices and their normals.
This removes visible seams along original edges, which were common previously.
With multiple branches it was possible the search could run for a long time,
especially when there was no possible path to the target.
Now use a heap to keep track of the best path and finish immediately once its reached.
Current behavior of bevel is to 'loop slide' along unbeveled edges
when possible, but this produces uneven bevel widths sometimes,
so this option lets user choose between having the loop slide effect
or having more even bevel widths. Trying it out with default being
'no loop slide', so different from current behavior. May reverse this
choice later, depending on user reactions.
Angle limit for join-faces was more advice then actual limit.
Now joining entire selection, gives assurance that no faces above the limit will be merged.
The purpose of this was to allow users to isolate 2 faces and always join them.
Instead, support this by bypassing limit only when its not set and 2 faces are selected.
