Implemented command-line control of log level

Change-Id: I9d03c0a67856710f8ade5d98cdcdf26dd4277275
diff --git a/src/util/logging.cpp b/src/util/logging.cpp
index b067c80..d26b11d 100644
--- a/src/util/logging.cpp
+++ b/src/util/logging.cpp
@@ -42,11 +42,13 @@
 namespace ndn {
 namespace ntorrent {
 
+log::severity_level LoggingUtil::severity_threshold = log::info;
+
 void LoggingUtil::init()
 {
   logging::core::get()->set_filter
   (
-      logging::trivial::severity >= SEVERITY_THRESHOLD
+      logging::trivial::severity >= severity_threshold
   );
 
   logging::add_file_log
diff --git a/src/util/logging.hpp b/src/util/logging.hpp
index d10e926..e6a2b4b 100644
--- a/src/util/logging.hpp
+++ b/src/util/logging.hpp
@@ -28,8 +28,6 @@
 #include <boost/log/sources/severity_logger.hpp>
 #include <boost/log/trivial.hpp>
 
-enum { SEVERITY_THRESHOLD = boost::log::trivial::debug };
-
 // register a global logger
 BOOST_LOG_INLINE_GLOBAL_LOGGER_DEFAULT(logger, boost::log::sources::severity_logger_mt<boost::log::trivial::severity_level>)
 
@@ -47,7 +45,11 @@
 namespace ndn {
 namespace ntorrent {
 
+namespace log = boost::log::trivial;
+
 struct LoggingUtil {
+  static log::severity_level severity_threshold;
+
   static void init();
   // Initialize the log for the application. THis method must be called in the main function in
   // the application before any logging may be performed.