NFD+ci+docs: Attaching NFD as a submodule

Based on NFD:commit:27be0b0d41235609bee703f4f2ef9e5b1978fdce (version 0.2.0-74-g27be0b0)

Change-Id: I7f9117b226aa244e257375f7f4c045dc9c4cd897
Refs: #3124
diff --git a/docs/source/getting-started.rst b/docs/source/getting-started.rst
index 9a5d0aa..cea91d2 100644
--- a/docs/source/getting-started.rst
+++ b/docs/source/getting-started.rst
@@ -124,7 +124,7 @@
     git clone https://github.com/named-data/ndn-cxx.git ndn-cxx
     git clone https://github.com/named-data-ndnSIM/ns-3-dev.git ns-3
     git clone https://github.com/named-data-ndnSIM/pybindgen.git pybindgen
-    git clone https://github.com/named-data-ndnSIM/ndnSIM.git ns-3/src/ndnSIM
+    git clone --recursive https://github.com/named-data-ndnSIM/ndnSIM.git ns-3/src/ndnSIM
 
 The few modification to the base NS-3 code are necessary to run ndnSIM, and the code is
 periodically synchronized with the official developer branch.  Eventually, all the changes will
@@ -256,7 +256,7 @@
         cd ndnSIM
         git clone https://github.com/named-data-ndnSIM/ns-3-dev.git ns-3
         git clone https://github.com/named-data-ndnSIM/pybindgen.git pybindgen
-        git clone https://github.com/named-data-ndnSIM/ndnSIM.git ns-3/src/ndnSIM
+        git clone --recursive https://github.com/named-data-ndnSIM/ndnSIM.git ns-3/src/ndnSIM
 
         # Build and install NS-3 and ndnSIM
         cd ns-3