face: Implementing close operation and many related fixes in TcpFace and TcpChannel

Change-Id: Ib6b751e80454e149bf94f3867663d5e705cbf4a0
refs: #1250, #1248
diff --git a/tests/face/dummy-face.hpp b/tests/face/dummy-face.hpp
index c7b5d76..e78f4cc 100644
--- a/tests/face/dummy-face.hpp
+++ b/tests/face/dummy-face.hpp
@@ -31,6 +31,11 @@
   sendData(const Data& data)
   {
   }
+
+  virtual void
+  close()
+  {
+  }
 };
 
 } // namespace nfd