Do not localize object properties, except WebSettings

Do not localize object properties, except WebSettings

Property name localization is only useful if the
strings are meant to be used in a user interface,
such as is the case with WebSettings, or for
graphical interface builders, which are not of
our concern, since we don't use Glade and friends
and nobody else is going to use our widgets.

In short, make translation work much easier.