This change adds OnData(Delisting data) event handler to the algorithm and is fired when a security gets delisted.
Likewise, when a security is delisted, data will stop being sent into the algorithm and if the algorithm has any
holdings then a MarketOnClose order is submitted at midnight on the last day of trading. If you require that the
algorithm does not sell its shares, then you must cancel the MarketOnClose order before close of trading.
Jared Broad