clamp( min, max ) {

		// assumes min < max, componentwise

		this.x = clamp( this.x, min.x, max.x );
		this.y = clamp( this.y, min.y, max.y );
		this.z = clamp( this.z, min.z, max.z );

		return this;

	}
If this vector's x, y or z value is greater than the max vector's x, y or z
value, it is replaced by the corresponding value.
If this vector's x, y or z value is less than the min vector's x, y or z value,
it is replaced by the corresponding value.

@param {Vector3} min - The minimum x, y and z values.
@param {Vector3} max - The maximum x, y and z values in the desired range.
@return {Vector3} A reference to this vector.