fill_solid -   fill a range of LEDs with a solid color

Example: fill_solid(leds, NUM_LEDS, CRGB(50,0,200));


fill_rainbow - fill a range of LEDs with a rainbow of colors, at full saturation and full value (brightness)

fill_rainbow(leds, NUM_LEDS, initialhue, deltahue);
fill_rainbow(leds, NUM_LEDS, 20, 3);



fill_gradient