app: bring dialog titles and help IDs to GEGL filter dialogs

Add "title" and "help_id" parameters and members/properties to
GimpToolDialog, GimpToolGui, GimpOperationTool. Also make the order of
parameters more consistent.

app/display/gimptooldialog.h

@@ -45,7 +45,10 @@ GType       gimp_tool_dialog_get_type (void) G_GNUC_CONST;
 GtkWidget * gimp_tool_dialog_new       (GimpToolInfo     *tool_info,
                                         GdkScreen        *screen,
                                         gint              monitor,
-                                        const gchar      *desc,
+                                        const gchar      *title,
+                                        const gchar      *description,
+                                        const gchar      *icon_name,
+                                        const gchar      *help_id,
                                         ...) G_GNUC_NULL_TERMINATED;
 
 void        gimp_tool_dialog_set_shell (GimpToolDialog   *tool_dialog,