ST some time ago decided to disable SysTick Callback. But they kept all
functions. It think it prevents from heavy code in SysTick so you
should be careful what are you doing. FX lib onli decrease one variable
I think it's light enough to put it into SysTick interrupt :)"
Based in WS2812BFX Arduino library by kitesurfer1404.
Every effect concerns whole strip - no segments.
I added also HSV color mode and two FX modes related to it.