Bollinger Bands with 3SD and BUY-SELL Basis

*The white lines(both inner and outer ones) are from original Bollinger Bands (calculated as SMA20+SD and SMA20-SD).
*Inner lines are calculated with 2 Standard Deviation ( as classical Bollinger Bands ) and outer ones are with 3 Standard Deviation.
*3 SD calculation is important because, it is useful to investigate further the volatility.
*Classical Bollinger Bands Basis is included in calculations to obtain the bands, but the basis isn't plotted (SMA20).
*For Basis, a-13 bar EMA line is added which tells "BUY" when GREEN, and which tells "SELL" when RED.
*Generally, this code is good to further investigate the volatility especially by the help of 3SD lines. It is particularly important for crypto currencies which are generally highly volatile. On the other hand, the basis will tell BUY-SELL points and BUY-SELL points can be confirmed further, by investigating classical Bollinger Bands rules and anticipate about the volatility.