Adding in boost::asio support

main starts a thread that keep a global io_service object
running and makes sure it is stopped when everything else is
stopped.

pglab/GlobalIoService.cpp

@@ -0,0 +1,7 @@
+#include "GlobalIoService.h"
+
+std::shared_ptr<boost::asio::io_service> getGlobalAsioIoService()
+{
+    static auto ios = std::make_shared<boost::asio::io_service>();
+    return ios;
+}