FinQuant v0.2

This version adds yfinance alongside quandl in order to download historical stock prices.

The documentation, Readme, examples, and tests have been updated to account for the new option yfinance.

Obtaining historical stock prices from quandl remains the default option.

Testing:
All examples in ./example/ are now automatically tested for failure.

Documentation:

• A bash script is included to automatically copy example python files in ./example/ to ./docs/, slightly modify to reduce the number of lines, and are now included in the documentation. A download link is also provided for each example.
• docstrings have been improved in some places for a cleaner/better automated documentation