build: require gcc >= 4.8.2 and boost >= 1.54.0

Change-Id: I230ac74f3fd1e7912c1645f36383913ff5bd3d2c
Refs: #3599
diff --git a/src/util/time.hpp b/src/util/time.hpp
index e0f64c5..976a27b 100644
--- a/src/util/time.hpp
+++ b/src/util/time.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2013-2014 Regents of the University of California.
+ * Copyright (c) 2013-2016 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -186,7 +186,7 @@
  * \param format desired output format (default: `%Y-%m-%d %H:%M:%S`)
  * \param locale desired locale (default: "C" locale)
  *
- * \sa http://www.boost.org/doc/libs/1_48_0/doc/html/date_time/date_time_io.html#date_time.format_flags
+ * \sa http://www.boost.org/doc/libs/1_54_0/doc/html/date_time/date_time_io.html#date_time.format_flags
  *     described possible formatting flags
  **/
 std::string
@@ -204,7 +204,7 @@
  * \param format    input output format (default: `%Y-%m-%d %H:%M:%S`)
  * \param locale    input locale (default: "C" locale)
  *
- * \sa http://www.boost.org/doc/libs/1_48_0/doc/html/date_time/date_time_io.html#date_time.format_flags
+ * \sa http://www.boost.org/doc/libs/1_54_0/doc/html/date_time/date_time_io.html#date_time.format_flags
  *     described possible formatting flags
  */
 system_clock::TimePoint