removeIfNonNeighbor method
Implementation
void removeIfNonNeighbor(Vertex n ) {
final neighbors = this.neighbors;
final faces = this.faces;
final offset = neighbors.indexOf( n );
if ( offset == - 1 ) return;
for (int i = 0; i < faces.length; i ++ ) {
if (faces[ i ].hasVertex( n ) ) return;
}
neighbors.removeAt(offset);
}