static averageDirection(vecs) {
    let avg = new Vector2(0.0, 0.0);

    for (var i = 0; i < vecs.length; i++) {
      let vec = vecs[i];
      avg.add(vec);
    }

    return avg.normalize();
  }
Returns the average vector (normalized) of the input vectors.

@static
@param {Array} vecs An array containing vectors.
@returns {Vector2} The resulting vector (normalized).