osx: Implement auto-upgrade function using Sparkle

During the upgrade, NFD and ndn-autoupdate will be stopped (and, if
enabled, automatically started with new versions).

Change-Id: I010ae4a8aa6f99a0039d58065ab7eb0c9189a979
diff --git a/src/main.cpp b/src/main.cpp
index d03f0cd..e39e70c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -140,7 +140,7 @@
 
   ForwarderStatusModel m_forwarderStatusModel;
   FibStatusModel m_fibModel;
-  TrayMenu m_tray;
+  ncc::TrayMenu m_tray;
 };
 
 } // namespace ndn