Revamp our handling of settings

The current handling of settings is a very roundabout leftover from the days of
gconf. Simplify and handle the setting more directly. At the same time move
handling of saving the window state to gsettings instead of saving it to a
config file.

xed/xed-window.h

@@ -106,6 +106,8 @@ gboolean   _xed_window_is_fullscreen (XedWindow *window);
 void _xed_recent_add (XedWindow *window, GFile *location, const gchar *mime);
 void _xed_recent_remove (XedWindow *window, GFile *location);
 
+void _xed_window_get_default_size (gint *width, gint *height);
+
 G_END_DECLS
 
 #endif /* __XED_WINDOW_H__ */