Changed the Order.TimeStamp property to DateTime from string.
Changed the Position.OpenProfitLossQty property to decimal from int.
Set the Json property name of GroupOrder.GroupOrderType to 'Type'
Changed ExpiresIn property so it counts down the number of seconds from when the token was issued. Added event which fires once when the token is within 120 seconds of expiration.
Readme and .csproj updates from recent changes.