ENH: snappyHexMesh: work better on non-manifold. Fixes ##3361

Summary

• Handle inside/outside for incorrectly oriented surfaces
• adds 'smoothTriSurfaceMesh' version of triSurfaceMesh with interpolated normals

Resolved bugs (If applicable)

#3361 (closed)

Risks

• orients normals consistently so will behave differently from previous
• limited testing of smoothTriSurfaceMesh

assigned to @andy

added 5 commits

• b5ebcc80...a3f74d83 - 4 commits from branch develop
• b79cbfe4 - ENH: snappyHexMesh: work better on non-manifold. Fixes ##3361 (closed)

Compare with previous version

In some corner cases, use of smoothTriSurface was still not enough to identify correct side of normal/flip check. @Mattijs

added 20 commits

• b79cbfe4...ffea1369 - 19 commits from branch develop
• 849a2a56 - ENH: snappyHexMesh: work better on non-manifold. Fixes ##3361 (closed)

Compare with previous version

added 1 commit

• f041c7d4 - ENH: snappyHexMesh: revert orientation for triSurface. See #3391

Compare with previous version

added 6 commits

• f041c7d4...fe0ba07a - 4 commits from branch develop
• 0cc933ac - ENH: snappyHexMesh: work better on non-manifold. Fixes ##3361 (closed)
• 5fc5c67f - ENH: snappyHexMesh: revert orientation for triSurface. See #3391

Compare with previous version

merged

mentioned in commit 96872f03