Added lerp15by16 as well as improved performance on some of the scaling functions on avr.
CRGB::lerp should be using 8by8, not 16by8.  Add operator>>= for fast shifting of rgb values in a pixel if wanted.
Adding 8 and 16 bit simplex noise implementations to the library.  The 8 bit version can do over 30,000 noise points per second, the 16 bit version over 15,000.  Also, add a debugging FPS counter to FastLED.
Merge branch 'FastLED2.1' of https://github.com/FastLED/FastLED into FastLED2.1
bumping release notes.