Liquidate Method Does Not Have Asynchronous and OrderProperties Option

[AlexCatarino]

Expected Behavior

The Liquidate method can place asynchronous orders not set the order properties.

Actual Behavior

Liquidate once place synchronous orders or set their properties.

Potential Solution

Option 1: The signature of the order methods in QCAlgorithm has the asynchronous parameter before the tag, so we should not add a parameter at the end. Instead, we need more method overloads.
Option 2: If the first argument is null, Liquidate should be asynchronous.

Reproducing the Problem

N/A. I noticed that a live algorithm wanted to open and close positions asynchronously. While there is an option using market orders to open the positions, it used Liquidate to close them and the orders were synchronous.

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