Add support for SK6812

[ajfisher]

As these are starting to become more available and are largely the same as the WS2812, add direct support for these by being able to shift a little faster on the HIs.

[ebrearley]

+1
I have 300 of these in my living room, installed them yesterday. I'd love to help out by adding this support, but on account of being a complete newbie and only understanding 20% of things right now, I'll just leave my plus one here 😝

[djipco]

Is there really a difference? Some people say that SK6812 are simply clones of WS2812b which would make them functionally equivalent.

I believe I'm currently using SK6812 LEDs from Adafruit and they work fine with the library.

If SK6812-based LEDs are supported, this issue should be closed because it introduces a lot of confusion. I, for one, saw this issue and thought SK6812 would not work which is not my experience.

This issue introduces further confusion because somebody mentions RGBW, which is another topic completely.

[TigerChi]

+1
Now I use Johnny-five control most of device, and another Arduino board to control SK6812 by UART....
If node-pixel can support RGBW it will be great !