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.

CMakeLists.txt

@@ -2,6 +2,7 @@ cmake_minimum_required(VERSION 3.1.0)
 project(pglaball)
 
 set (CMAKE_PREFIX_PATH /usr/lib/x86_64-linux-gnu/qt5/mkspecs/features/data/cmake)
+set (CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/Modules/")
 
 find_package(PkgConfig REQUIRED)
 
@@ -52,8 +53,11 @@ include_directories( ${Qt5Widgets_INCLUDE_DIRS} )
 find_package(fmt 4.0 REQUIRED)
 include_directories( ${fmt_INCLUDE_DIRS} )
 
-#find_package(Boost 1.62 REQUIRED) # COMPONENTS program_options REQUIRED )
-#include_directories( ${Boost_INCLUDE_DIRS} )
+#find_package(Libevent 2.0 REQUIRED)
+#include_directories( ${Libevent_INCLUDE_DIRS} )
+
+find_package(Boost 1.63 COMPONENTS system REQUIRED )
+include_directories( ${Boost_INCLUDE_DIRS} )
 
 add_library(core STATIC
     core/BackupFormatModel.cpp
@@ -75,6 +79,7 @@ add_executable(pglab
     pglab/DatabasesTableModel.cpp
     pglab/DatabaseWindow.cpp
     pglab/ExplainTreeModelItem.cpp
+    pglab/GlobalIoService.cpp
     pglab/jsoncpp.cpp
     pglab/main.cpp
     pglab/MainWindow.cpp