Exposed AJ_UnmarshalArgs() to Javascript. Since JS doesn't support pass by reference, this function returns an array that has:
+ Index 0: AJ_Status
+ Index 1..n: return params that have format described in signature
Usage:
   var retObj = AllJoynWinRTComponent.AllJoyn.aj_UnmarshalArgs(msg, 'uu');
   var status = ret[0];
   var replyCode = ret[1];
   var sessionId = ret[2];