Added an IPersonHeldPositions adapter that gets positions sorted by
status : a main position, all current positions, closed positions.
Contact details of a person fallbacks to person's main position
get from IPersonHeldPositions adapter.
Merge branch 'master' of github.com:collective/collective.contact.core
we can query only few keys on get_contact_details method
sort held positions on person view
organization label is a link on heldpositions block
more robust show contact details
css class for ttwfields
Merge branch 'master' of github.com:collective/collective.contact.core

Conflicts:
	CHANGES.rst
setup relation dependency work in overlays
setup relation dependency works even if we don't have modified value yet
(with value already set on edit form)
Merge branch 'master' of github.com:collective/collective.contact.core

Conflicts:
	CHANGES.rst
sort held positions on organization view not on content