removeVertexFromFace (vertex, face) {
    if (vertex === face.outside) {
      // fix face.outside link
      if (vertex.next && vertex.next.face === face) {
        // face has at least 2 outside vertices, move the `outside` reference
        face.outside = vertex.next
      } else {
        // vertex was the only outside vertex that face had
        face.outside = null
      }
    }
    this.claimed.remove(vertex)
  }
Removes `vertex` for the `claimed` list of vertices, it also makes sure
that the link from `face` to the first vertex it sees in `claimed` is
linked correctly after the removal

@param {Vertex} vertex
@param {Face} face