Bug 1023735 - [Settings] Support new time format settings

- change langauge -> update timeformat
- add default settings and l10n properties
- change timeZone -> redraw time field with user pref
- change time/dateFormat -> update time/date field with user pref
- change date/time field -> correct set date/time
- change date field -> redraw dateFormat with user pref
- add navigator.mozHour12 API shim
We should use `navigator.mozL10n.DateTimeFormat` so the result will align to what we see in the language panel.