core: move common.hpp to core/

Headers in core/ are now included as `#include "core/*.hpp"`.
This allows NFD to rely less on include paths when used as a submodule in
another codebase, such as ndnSIM and NFD-Android.

refs #3127

Change-Id: Ia38f3c97427e17ff7b5401281f1fe875b5d5313e
diff --git a/daemon/mgmt/general-config-section.cpp b/daemon/mgmt/general-config-section.cpp
index ed6f99e..2b573b3 100644
--- a/daemon/mgmt/general-config-section.cpp
+++ b/daemon/mgmt/general-config-section.cpp
@@ -1,11 +1,12 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2014  Regents of the University of California,
- *                     Arizona Board of Regents,
- *                     Colorado State University,
- *                     University Pierre & Marie Curie, Sorbonne University,
- *                     Washington University in St. Louis,
- *                     Beijing Institute of Technology
+ * Copyright (c) 2014-2016,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
  *
  * This file is part of NFD (Named Data Networking Forwarding Daemon).
  * See AUTHORS.md for complete list of NFD authors and contributors.
@@ -20,11 +21,10 @@
  *
  * You should have received a copy of the GNU General Public License along with
  * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
- **/
+ */
 
 #include "general-config-section.hpp"
 
-#include "common.hpp"
 #include "core/logger.hpp"
 #include "core/privilege-helper.hpp"
 #include "core/config-file.hpp"