fw: rename BroadcastStrategy to MulticastStrategy

BroadcastStrategy is temporarily retained for backwards compatibility.

This commit also updates nfd.conf and ndn-autoconfig to use MulticastStrategy
in place of BroadcastStrategy.

refs #3011

Change-Id: I011f1cf75db26b3c93552f8322a0bba4ce8dd033
diff --git a/daemon/mgmt/tables-config-section.cpp b/daemon/mgmt/tables-config-section.cpp
index c7661ce..f0b9eaf 100644
--- a/daemon/mgmt/tables-config-section.cpp
+++ b/daemon/mgmt/tables-config-section.cpp
@@ -84,9 +84,9 @@
   //    strategy_choice
   //    {
   //       /               /localhost/nfd/strategy/best-route
-  //       /localhost      /localhost/nfd/strategy/broadcast
+  //       /localhost      /localhost/nfd/strategy/multicast
   //       /localhost/nfd  /localhost/nfd/strategy/best-route
-  //       /ndn/broadcast  /localhost/nfd/strategy/broadcast
+  //       /ndn/broadcast  /localhost/nfd/strategy/multicast
   //    }
   // }
 
@@ -133,9 +133,9 @@
   // strategy_choice
   // {
   //   /               /localhost/nfd/strategy/best-route
-  //   /localhost      /localhost/nfd/strategy/broadcast
+  //   /localhost      /localhost/nfd/strategy/multicast
   //   /localhost/nfd  /localhost/nfd/strategy/best-route
-  //   /ndn/broadcast  /localhost/nfd/strategy/broadcast
+  //   /ndn/broadcast  /localhost/nfd/strategy/multicast
   // }
 
   std::map<Name, Name> choices;