If held position implements IContactDetails behavior,
then show contact details fields on add contact form.
Fix: Hide use parent address:
     - works in overlays,
     - always display use parent address on held position if it
implements contact details.
UI: use classes instead of ids on address because it can be used
  several times on the same page.
pylint, jshint
console.log
oups
Merge branch 'master' of git@github.com:collective/collective.contact.core.git
more robust AND specific method to check if parent address is empty on
contact form