rotateAround( center, angle ) {

		const c = Math.cos( angle ), s = Math.sin( angle );

		const x = this.x - center.x;
		const y = this.y - center.y;

		this.x = x * c - y * s + center.x;
		this.y = x * s + y * c + center.y;

		return this;

	}
Rotates this vector around the given center by the given angle.

@param {Vector2} center - The point around which to rotate.
@param {number} angle - The angle to rotate, in radians.
@return {Vector2} A reference to this vector.