Updated Stage class.

- Color property still returns a hexadecimal representation of the color but now without the '#' at the start. Changed to be more consistent with how you set the hex color.
- Can now set/get the color of the stage via RGB values. Property 'rgbColor' and method 'setRGBColor' handle it.
- 'createDebugCanvas' is now public, since it is not longer automatically created.
- Comments around the debug canvas have been added/updated.