* Instead of deleting contacts altogether from the main contact list when de-duping,
  keep them in the list.
* De-dup names first.
* If contact given name or first name is either nil or only has
  one value, contact is merged. (Last name is not that meaningful,
  since it can often be left out.)
* If the contact's longest name includes shorter names, contact
  is merged. (This means that things like "Owner Maria Pacana"
  will automatically include "Maria Pacana"!)