Support for SM16716

Added support for SM16716 controller (sometimes selled instead of WS2801). The documentation of this controller is available here: http://www.chinaasic.com/datasheet/SM16716%20datasheet%20cn.pdf (Chinese only).
Summary:
* Every frame starts with 50 bits set "0", followed by the pixelvalues.
* A pixelvalue has 25 bits: 1 bit set to "1" + RGB.

Others:
* I can not turn off my LEDs with the default "BLACK". 
* And I'm not sure what the gamma correction is for (the colors are closest without the correction for me)