allow GUI window layout to be restored * main-window.h, main-window.cc (main_window::set_window_layout): New function. (main_window::read_settings): Call set_window_layout for current settings. (main_window::reset_windows): Call set_window_layout for default settings. (main_window::construct_window_menu): Enable reset_windows_action. * resource-manager.h, resource-manager.cc (default_qt_settings_file): Return QString instead of std::string. Change all callers. (resource_manager::default_settings): New member variable. (resource_manager::resource_manager): Initialize default_settings. (resource_manager::~resource_manager): Delete default_settings. (resource_manager::get_default_settings, resource_manager::do_get_default_settings): New functions. (resource_manager::do_is_first_run, resource_manager::do_get_settings, resource_manager::do_get_home_path): Now const.

--- a/libgui/src/main-window.h
+++ b/libgui/src/main-window.h
@@ -135,6 +135,7 @@
                                                 const QString& file, int line);
 
   void read_settings (void);
+  void set_window_layout (QSettings *settings);
   void write_settings (void);
   void connect_visibility_changed (void);