added calculator module
added keys to methods for flexibility
testing module for calc
tested variance and covariance
added tests for percent change, percent change array, find index and stdev
separated calculator into risk and normal
adding risk tests
created fake portfolios, risk free and benchmarks for calculations
calculating total returns
adding on risk testing suite
added sharpe calculator
added volatility calc
added returns calc to Calc class and adding tests
added more values to stock data and market data
redefined how data is stored, nested more robustly
first working test of returns calculator
finished first return checking test
finished returns calculator tests
added assess current portfolio value method to portfolio calculator
added method for calculating returns of each asset in portfolio with test