Histogram ATR-SMA(ATR) by drinchi

Indicator make histogram from difference of:
- classic ATR (default period - 14)
- Simple Moving Average (default period - 100) to this ATR.

Histogram colored (green when >0, red <0).
Volatility increase signal - histogram crosses the zero line.

For greater visibility, a colored variable moving average (variable SMA for histogram) was added
(green when increase, red when decrease).