Update surface.attach and change surface.map to surface.map_toplevel

The new map_toplevel() request no longer specifies a position and takes
the size from the attached buffer.  The attach request now takes a
position relative to the top-left corner of the old buffer to let
clients specify the relative position of the new buffer.
diff --git a/compositor/compositor-wayland.c b/compositor/compositor-wayland.c
index 40dee58..b216ebd 100644
--- a/compositor/compositor-wayland.c
+++ b/compositor/compositor-wayland.c
@@ -193,7 +193,8 @@
 					  output->rbo[output->current]);
 
 		wl_surface_attach(output->parent.surface,
-				  output->parent.buffer[output->current ^ 1]);
+				  output->parent.buffer[output->current ^ 1],
+				  0, 0);
 		wl_surface_damage(output->parent.surface, 0, 0,
 			          output->base.width, output->base.height);
 	}
@@ -264,10 +265,8 @@
 				  output->rbo[output->current]);
 
 	wl_surface_attach(output->parent.surface,
-			  output->parent.buffer[output->current]);
-	wl_surface_map(output->parent.surface,
-		       output->base.x, output->base.y,
-		       output->base.width, output->base.height);
+			  output->parent.buffer[output->current], 0, 0);
+	wl_surface_map_toplevel(output->parent.surface);
 
 	glClearColor(0, 0, 0, 0.5);