Add "presenter" as possible default_layout

doc/katarakt.txt

@@ -140,7 +140,7 @@ VARIABLES
 'string' *background_color_fullscreen* ::
 	0xFF000000: Fullscreen background color in ARGB Format.
 'string' *default_layout* ::
-	presentation: The layout on startup. Possible values: 'presentation', 'grid'.
+	presentation: The layout on startup. Possible values: 'presentation', 'grid', 'presenter'.
 'int' *mouse_wheel_factor* ::
 	120: QT delta for turning the mouse wheel 1 click.
 'int' *smooth_scroll_delta* ::

share/katarakt.ini

@@ -27,6 +27,7 @@ single_instance_per_file=false
 [Keys]
 set_presentation_layout=1
 set_grid_layout=2
+set_presenter_layout=3
 page_up=PgUp
 page_down=PgDown
 page_first=Home, G

src/canvas.cpp

@@ -88,6 +88,8 @@ Canvas::Canvas(Viewer *v, QWidget *parent) :
 	QString default_layout = config->get_value("default_layout").toString();
 	if (default_layout == "grid") {
 		cur_layout = grid_layout;
+	} else if (default_layout == "presenter") {
+		cur_layout = presenter_layout;
 	} else { // "presentation" and everything else
 		cur_layout = presentation_layout;
 	}