Add more menus and endless mode

objects/o_mode_menu/Step_0.gml

@@ -0,0 +1,16 @@
+if global.back_key_pressed {
+	instance_destroy();
+	
+	instance_create_depth(0, 0, -9000, o_start_menu);
+}
+
+if global.one_key_pressed {
+	instance_destroy();
+}
+
+if global.two_key_pressed {
+	global.infinite_mode = true;
+	global.enemy_active_max = 100;
+	
+	instance_destroy();
+}