NFD+model+apps+helper+tests: Upgrade NFD and related changes

Based on NFD:commit:2fc649bfc67b93b4191cfbee5bcd70330bfb48f0 (version 0.3.4)

Change-Id: I89f5182600467171797af4f8f83e1edffe14ad95
Refs: #3125
diff --git a/.gitignore b/.gitignore
index 8cc655a..d8a5d6e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,4 +4,5 @@
 *~
 .DS_Store
 docs/doxygen.warnings.log
-
+docs/introspected-doxygen.hpp
+docs/ndnSIM.tag