WAResponse >>#doNotCache doesn't send full Cache-Control header

```
The header to suppress caching should be

  Cache-Control: no-cache, max-age=0, must-revalidate, no-store

#doNotCache omits max-age and no-store in my build of seaside 3.1

On Chrome latest version the full header is needed to force a reload on 
back-button use
```

Original issue reported on code.google.com by `rainbowt...@gmail.com` on 4 Dec 2013 at 12:49
