A few code reorganizations

Change-Id: If4632fecc7085e5448226c2061e08546757eda9b
diff --git a/core/db.cpp b/core/db.cpp
index 22474df..d87707f 100644
--- a/core/db.cpp
+++ b/core/db.cpp
@@ -25,7 +25,8 @@
 #include <string>
 #include <boost/filesystem.hpp>
 
-namespace nsl {
+namespace ndn {
+namespace delorean {
 
 static const std::string INITIALIZATION =
   "CREATE TABLE IF NOT EXISTS                    \n"
@@ -306,4 +307,5 @@
   return m_nextLeafSeqNo;
 }
 
-} // namespace nsl
+} // namespace delorean
+} // namespace ndn