Whispertrades

- Update API specs for bot.EntryCondition and bot.Adjustments (min/max iv, vix, %move from open)
- Add trailing_stop_sensitivity to bot.ExitCondition
- Add broker.rebalance_collateral API

- Add BrokerConnection API

**Full Changelog**: https://github.com/aliencaocao/whispertrades/compare/0.1.0...0.1.1

Initial release

All APIs exposed as of the time of release have been implemented but not well-tested yet. Please use with caution and welcome to open issues/provide feedback!