More examples / tests.
Switch palette from R,G,B split compontents to a single combined RGB component.
This means the palette length should now be a power of 2, not a power of 2
times 3.  The palette is now of the form [RGB, RGB, ...] and not the previous
[R, G, B, R, G, B, ...].  This makes the palette copy a little more complicated
but makes the API a bit more convenient in some cases.