fw: Forwarder processes Link for mobility

This commit also adds NetworkRegionTable to store producer region names,
and checks packets are well-formed before entering forwarding pipelines.

refs #3034, #3155

Change-Id: I8de4c482e8a289b922be70139675bc4661f9a301
diff --git a/common.hpp b/common.hpp
index 5e6724a..bd8f10b 100644
--- a/common.hpp
+++ b/common.hpp
@@ -98,6 +98,7 @@
 using ndn::Data;
 using ndn::Name;
 using ndn::Exclude;
+using ndn::Link;
 using ndn::Block;
 using ndn::util::FaceUri;