rotate(angle, v) {
		if (angle !== 0) {
			this.currentTransform.rotate(angle, v);
			this.updateBounds();
			this.isDirty = true;
		}
		return this;
	}
Rotate this renderable by the specified angle (in radians).
@param {number} angle - The angle to rotate (in radians)
@param {Vector2d|ObservableVector2d} [v] - an optional point to rotate around
@returns {Renderable} Reference to this object for method chaining