Protocol support for RGBW

[a-v-s]

The protocol specified command 0x00 to send RGB data per pixel. As there are now LED strips with an additional white led, which expect RGBW data, which contains an additional 8 bit value for the white led.

In order to control such LED strips I propose to add support for RGBW data to the protocol. The command 0x01 could be defined to have 32 bit per pixel data containing four bytes Red, Green, Blue and White.

[AustinSaintAubin]

Additinally, the common chipset for RGBW LEDs is SK6812.

[simon-budig]

For some applications it also might be useful to provide RGBA data.

Instead of using up the (scarce) commands for a variety of possible pixel data formats (there are DMX lights with tons of components like RGB, Amber, UV etc...) I'd extend command 1 with a to-be-defined color space identifier.

[a-v-s]

Apart from DMX lights, there are now WWA (Cool white, Warm white, Amber) SK6812 strips available.
Indeed, we could specify a colour space, and a number of elements, as parameters to be sent in front of the data.