update demo window

src/main.c

@@ -25,10 +25,8 @@ client_poll_event()
 void
 client_update_framebuffer()
 {
-	// single green demo pixel
-	game_state->framebuffer[0] = 0x00FF00;
-
-	put_rect(0, 0, 1100, 200, 0xFFFF00);
+	// example window contents
+	clear_framebuffer(0xFFFF00);
 	put_string("Hello, traveller. You have come\nto the right place!",
 		20, 20, 2, 2, 3, 0x000000, 0xFFFF00
 	);
@@ -39,6 +37,8 @@ main()
 {
 	// initialize the engine
 	if (engine_init(
+		500, 100,
+		"Dangerzone",
 		client_poll_event,
 		client_update_framebuffer
 	)) {