addColors( color1, color2 ) {

		this.r = color1.r + color2.r;
		this.g = color1.g + color2.g;
		this.b = color1.b + color2.b;

		return this;

	}
Adds the RGB values of the given colors and stores the result in this instance.

@param {Color} color1 - The first color.
@param {Color} color2 - The second color.
@return {Color} A reference to this color.