* Add trailing stop orders base implementation
* Handle trailing stop order prices rounding
* Implement trailing stop orders fill logic
* Minor fill model changes
* Add ApplySplit to fill model interface for models that might need to be aware of splits.
Filling trailing stop orders require keeping track of min/max prices, which need to be split adjusted.
* Add brokerage order updated event for communicating certain order types prices changes
* Add order update event args class for brokerage side order updates
* Revert IFillModel.ApplySplit
* Add trailing stop orders regression algorithm
* Updated order ticket demo algorithm to include trailing stop orders
* Some cleanup
* Support trailing stop orders in IB brokerage model
* Some cleanup
* Fix failing tests
* Fix failing regression algorithm
* Address peer review
* Add trailing stop price calculation unit tests
* Minor changes
* Minor change
Ashutosh