function RGBColor(red, green, blue, alpha)
{
    this.red = red;
    this.green = green;
    this.blue = blue;
    this.alpha = alpha;
}
@class RGBColor
Stores an RGB color with red, green, blue, and alpha values.
All values are in the range [0.0 to 255.0]. Invalid numeric values are
converted to numbers within this range.

@param red   The red value, in the range [0.0 to 255.0].
@param green The green value, in the range [0.0 to 255.0].
@param blue  The blue value, in the range [0.0 to 255.0].
@param alpha The alpha (transparency) value, in the range [0.0 to 255.0].
     The default, 255.0, means that the color is fully opaque.

@return A new RGBColor object.