node+transport: Improving async operations and error reporting

All operations, including connect are fully async

Change-Id: I6c28c4f883d3aa10efbc4af939cf09e0e865c574
diff --git a/include/ndn-cpp/transport/unix-transport.hpp b/include/ndn-cpp/transport/unix-transport.hpp
index 9692cff..b7b65a9 100644
--- a/include/ndn-cpp/transport/unix-transport.hpp
+++ b/include/ndn-cpp/transport/unix-transport.hpp
@@ -22,8 +22,7 @@
   // from Transport
   virtual void 
   connect(boost::asio::io_service &ioService,
-          const ReceiveCallback &receiveCallback,
-          const ErrorCallback &errorCallback);
+          const ReceiveCallback &receiveCallback);
   
   virtual void 
   close();