oriented polyline

[cscorley]

closes #254

adds 2D version of TriMeshFlags::ORIENTED + TriMeshFlags::FixInternalEdges

[sebcrozet]

Thank you for this PR!

Another modification that is needed is the behavior of the implementation of PointQuery for Polyline so it mirrors the trimesh behavior. If a Polyline is oriented, then a point starting inside of it should be considered to be its own projection.

See for example the case of an oriented TriMesh:

parry/src/query/point/point_composite_shape.rs

Lines 288 to 311 in ef63da4

	#[cfg(feature = "dim3")]
	if let Some(pseudo_normals) = self.pseudo_normals_if_oriented() {
	let pseudo_normal = match location {
	TrianglePointLocation::OnFace(..) | TrianglePointLocation::OnSolid => {
	Some(self.triangle(part_id).scaled_normal())
	}
	TrianglePointLocation::OnEdge(i, _) => pseudo_normals
	.edges_pseudo_normal
	.get(part_id as usize)
	.map(|pn| pn[i as usize]),
	TrianglePointLocation::OnVertex(i) => {
	let idx = self.indices()[part_id as usize];
	pseudo_normals
	.vertices_pseudo_normal
	.get(idx[i as usize] as usize)
	.copied()
	}
	};
	if let Some(pseudo_normal) = pseudo_normal {
	let dpt = point - proj.point;
	proj.is_inside = dpt.dot(pseudo_normal) <= 0.0;
	}
	}

[sebcrozet]

Should be removed.

[sebcrozet]

Since pseudo-normals (and the PolylineFlags as well) are only relevant in 2d, they should be excluded from 3d using #[cfg(feature = "dim2")].