nodesOverlap = function nodesOverlap(node1, node2, dX, dY) {
  if (dX > 0) {
    var overlapX = node1.maxX - node2.minX;
  } else {
    var overlapX = node2.maxX - node1.minX;
  }

  if (dY > 0) {
    var overlapY = node1.maxY - node2.minY;
  } else {
    var overlapY = node2.maxY - node1.minY;
  }

  if (overlapX >= 0 && overlapY >= 0) {
    return Math.sqrt(overlapX * overlapX + overlapY * overlapY);
  } else {
    return 0;
  }
}
@brief  : Determines whether two nodes overlap or not
@return : Amount of overlapping (0 => no overlap)