Per UX feedback, relabel W0 buttons, always show OFF.

* Wikipedia Zero-related buttons and some croutons have new labels.
* Going from W0 On to W0 Off, always yields a dialog box now (instead of just first time dialog box).
* Croutons shown at same junctures as before.

Change-Id: I43401fe9f0af11b0a444035013e0e24bbab23f3c