src: Reorganizing source code in preparation to merge NRD code

Note that as of this commit, there are several changes in location of
compiled binaries in `build/` folder:

* `nfd` has been moved to `build/bin/nfd`
* `unit-tests` has been split into `unit-tests-core` and `unit-tests-daemon`

Change-Id: I2c830c117879edbaa5457d6423c13f0273285919
Refs: #1486
diff --git a/daemon/mgmt/status-server.cpp b/daemon/mgmt/status-server.cpp
index bb42a0e..148061c 100644
--- a/daemon/mgmt/status-server.cpp
+++ b/daemon/mgmt/status-server.cpp
@@ -24,7 +24,7 @@
 
 #include "status-server.hpp"
 #include "fw/forwarder.hpp"
-#include "core/version.hpp"
+#include "version.hpp"
 
 namespace nfd {