Added property for query string parameters

Property qs for SignalR connection could be used to pass additional parameters to new SignalR persistent/hub connections. It is available since 1.0 and is present in 2.0 version of SignalR

Please see 
http://stackoverflow.com/questions/13542453/signalr-1-0-send-data-to-a-specific-client which is posted November, 2012.