Make tetengo2::gui::cursor::details() non-optional
Correct lint warnings
Changed stub detail implementation of the transparent background
Changed Direct2D specific detail implementation of the transparent background
Changed GDI+ specific detal implementation of the transparent background
Make tetengo2::gui::drawing::background::details() non-optional
Correct lint warnings
Correct Doxygen warnings
Make tetengo2::gui::drawing::canvas::details() non-optional
Make tetengo2::gui::drawing::picture::details() non-optional
Make tetengo2::gui::menu::menu_base::details() non-optional
Modify the detail implementation of the shortcut key table
Make tetengo2::gui::menu::shortcut_key_table::details() non-optional
Make tetengo2::gui::widget::widget::details() non-optional
Make tetengo2::gui::widget::widget::vertical/horizontal_scroll_bar() non-optional and create has_vertical/horizontal_scroll_bar()
Make tetengo2::gui::icon::details() non-optional
Make tetengo2::detail::stub/windows::create_dialog/window() non-optional
Replace NULL to nullptr
Merge branch 'optref'