Make sure translate works with IntDisplayList and translate the value, r...

Hi,

InDisplayList was causing following error:

Line 2 Module Products.Archetypes.browser.utils, line 25, in translate TypeError: 'int' object is not iterable

Reported here: https://github.com/collective/Products.PloneSurvey/issues/2

I've fixed this, and also converted it to translate the value of the vocab item, rather than the key, so the translation appears in base_view.

Cheers
Michael