BacktestTool - batch backtest, import and strategy parameters optimalization

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New version was released today.

New features:

- Gekko BacktestTool external config file support. Default config is backtest-config.pl, but You can create own and use backtest.pl
- using TOML files for strategies configuration as default. Can be changed in backtest-config.pl
- percentage wins, best win, worst loss, median win, median lost, average exposed duration added to csv file.
- parameter --covert TOML_FILE. Convert toml file and print strategy settings in Gekko's config file format
- parameter exchange:ALL and exchange:asset:ALL for backtest pairs. Do backtest for all available pairs. Based on non empty tables from sqlite database.
- parameter exchange:ALL and exchange:asset:ALL for import pairs. Import all available pairs from exchange. Based on exchange/exchange-markets.json file
- parameter --import --from=last --to=now. The 'last' value checks in the database the time of the last candle for each pair and assign this value to --from. 'now' assign current time in GMT time zone. In short: with this command you can import from the last candle from datasets to current time.