jni: Initial implementation for NFD start/stop facility

Current limitations:
- fixed configuration

Change-Id: Ia6b47cc682f133c9c504b24211855e1904f2236e
Refs: #2509
diff --git a/.gitmodules b/.gitmodules
index 6ce4745..97b91e7 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,13 +1,13 @@
-[submodule "app/src/main/jni/ndn-cxx"]
-	path = app/src/main/jni/ndn-cxx
-	url = https://github.com/named-data/ndn-cxx
 [submodule "app/src/main/jni/cryptopp"]
-	path = app/src/main/jni/cryptopp
-	url = http://github.com/cawka/cryptopp
-	branch = android
+    path = app/src/main/jni/cryptopp
+    url = http://github.com/cawka/cryptopp
+    branch = android
 [submodule "app/src/main/jni/sqlite3"]
-	path = app/src/main/jni/sqlite3
-	url = https://github.com/cawka/sqlite3-android.git
+    path = app/src/main/jni/sqlite3
+    url = https://github.com/cawka/sqlite3-android.git
+[submodule "app/src/main/jni/ndn-cxx"]
+    path = app/src/main/jni/ndn-cxx
+    url = ../ndn-cxx
 [submodule "app/src/main/jni/NFD"]
-	path = app/src/main/jni/NFD
-	url = https://github.com/named-data/NFD
+    path = app/src/main/jni/NFD
+    url = ../NFD