Fast-trade

Bug Fixes
- fixed validation bug with "0" as datapoint
- pinning versions for safe install

BREAKING CHANGES
- strategies are now "backtests"
- backtests contain more logic
- backtest `indicators` column is now `datapoints`
- fix `comission` misspelling, it was `commission`

New Features
- DataDownloader via the cli
- added more logic fields `any_exit` and `any_enter`
- added trailing stop loss
- added confirmation/lookback periods for logics
- added a backtest validator

Testing
- now around 70% test coverage!

Fixes a Nan bug when the `exit_on_end` setting is true and still in a trade.

Bug Fixes
+ resampling bug where the index was reset and unused

Breaking changes
+ `run_backtest` now returns an additional dataframe accessed at `trade_log` on the return object. This is just a subset of the larger `df` object. See the docs for more information
+ `chart_period` has changed slightly and now uses [offset strings](https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#dateoffset-objects) from pandas
+ `commission` can now be added to the strategy included when backtesting
+ `buy_and_hold_perc` is now available on the summary object