Empyrial

- Switch Empyrial to yfinance
- Added Risk Manager (Max Drawdown, Take Profit, Stop Loss)
- Correction of Black Litterman optimizer

**All the credits goes to [Diego Alvarez](https://github.com/diegodalvarez)**

- Added "rebalance" as an Engine's argument
- Rebalancing available for "2y", "1y", "monthly", "quaterly"

- Fixings in Fundlens
- Adding possibility of resizing size and font of the pie with the optimizer()

- Added an optimizer function with 4 optimization methods: Equal weighting, Mean-Variance, General Efficient Frontier, HRP

- Fundamental lens added

Adding Oracle function which :
- contains several predictions models such as Exponential smoothing, Prophet, Auto-ARIMA, Theta(2), ARIMA, FFT, FourTheta, NaiveDrift, NaiveMean, NaiveSeasonal
- calculates MAPE for each of these models to check the accuracy
- predict returns of your assets and portfolio with all these models