cycle: clarify the lifecycle of window switcher

This commit clarifies the lifecycle of the window switcher (cycle) by:
- init_cycle(): initializes the window switcher (e.g. OSD).
- update_cycle(): updates the window switcher states including OSD,
  preview and outlines.
- destroy_cycle(): clears all the window switcher states.

This commit temporarily regresses by not trying to preserve the selected
view when a view is destroyed. This will be addressed in the next commit.

src/view.c

@@ -2616,7 +2616,9 @@ view_destroy(struct view *view)
 		zfree(view->tiled_region_evacuate);
 	}
 
-	cycle_on_view_destroy(view);
+	/* TODO: call this on map/unmap instead */
+	cycle_reinitialize(server);
+
 	undecorate(view);
 
 	view_set_icon(view, NULL, NULL);