v0.70.6

What's new

• Keep Normals (surface turn) — new default shape key export mode. Normals follow the real turn of the surface, so stylised (toon) face normals no longer swing where a key squashes eyelids or lips. Meshes with ordinary normals export the same as before. The previous mode is still available as Keep Normals (as in Blender).
• Static Normals — per shape key, in the Shape Keys panel (with All / None). An exported key keeps the authored normals, so it doesn't change the shading; a locked key is baked into the basis without changing its normals.
• Locked shape keys now bake with the authored normals turned by the surface, avoiding the same swing on stylised normals.

Fixes

• Custom normals are kept when quads and n-gons are triangulated on export. Stylised normals could previously be off by up to ~90 degrees.