function Point(curve, x, z) {
  Base.BasePoint.call(this, curve, 'projective');
  if (x === null && z === null) {
    this.x = this.curve.one;
    this.z = this.curve.zero;
  } else {
    this.x = new BN(x, 16);
    this.z = new BN(z, 16);
    if (!this.x.red)
      this.x = this.x.toRed(this.curve.red);
    if (!this.z.red)
      this.z = this.z.toRed(this.curve.red);
  }
}
Returns TRUE if the first specified array contains all elements
from the second one. FALSE otherwise.

@param {array} superset
@param {array} subset

@returns {boolean}