Get rid of cryptopp dependency

Plus various code cleanups:
 * More 'auto' usage
 * Use 'nullptr' instead of 0
 * Rename NewApp class to ChronoChatApp
 * Print exception info with boost::diagnostic_information()
 * Disable -Wdeprecated-copy and -Wredundant-tags, they trigger
   too many warnings in Qt headers with gcc 9 and later

Change-Id: I2ea16c19be634f957b59280c704a956f083891f0
diff --git a/src/chatroom-discovery-backend.cpp b/src/chatroom-discovery-backend.cpp
index 3f92e01..8e2ad21 100644
--- a/src/chatroom-discovery-backend.cpp
+++ b/src/chatroom-discovery-backend.cpp
@@ -9,19 +9,15 @@
  */
 
 #include "chatroom-discovery-backend.hpp"
+
 #include <QStringList>
 
-#ifndef Q_MOC_RUN
-
-#endif
-
 namespace chronochat {
 
 static const time::milliseconds FRESHNESS_PERIOD(60000);
 static const time::seconds REFRESH_INTERVAL(60);
 static const time::seconds HELLO_INTERVAL(60);
-static const ndn::Name::Component ROUTING_HINT_SEPARATOR =
-  ndn::name::Component::fromEscapedString("%F0%2E");
+static const Name::Component ROUTING_HINT_SEPARATOR = Name::Component::fromEscapedString("%F0%2E");
 // a count enforced when a manager himself find another one publish chatroom data
 static const int MAXIMUM_COUNT = 3;
 static const int IDENTITY_OFFSET = -1;
@@ -93,8 +89,6 @@
     close();
 
   } while (shouldResume);
-
-  std::cerr << "DiscoveryBackend: Bye!" << std::endl;
 }
 
 void