core: global io_service and scheduler

Scheduler and time are imported from ndn-cpp-dev.
Forwarder is using the new scheduler API.
Face system is not transitioned yet.

refs #1290

Change-Id: I5679cb50bbf9890a105f663b038f13951403c2b6
diff --git a/daemon/core/global-io.hpp b/daemon/core/global-io.hpp
new file mode 100644
index 0000000..7e961f1
--- /dev/null
+++ b/daemon/core/global-io.hpp
@@ -0,0 +1,30 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (C) 2014 Named Data Networking Project
+ * See COPYING for copyright and distribution information.
+ */
+
+#ifndef NFD_CORE_GLOBAL_IO_HPP
+#define NFD_CORE_GLOBAL_IO_HPP
+
+#include "common.hpp"
+
+namespace nfd {
+
+/** \return the global io_service instance
+ */
+boost::asio::io_service&
+getGlobalIoService();
+
+#ifdef WITH_TESTS
+/** \brief delete the global io_service instance
+ *
+ *  It will be recreated at the next invocation of getGlobalIoService.
+ */
+void
+resetGlobalIoService();
+#endif
+
+} // namespace nfd
+
+#endif // NFD_CORE_GLOBAL_IO_HPP