Issue #1093928 Required option lists do not have an empty option available. Add one to avoid 'An illegal choice has been detected' errors for empty groups.

- Fix warning: Creating default object from empty value in template_preprocess_content_display_overview_form() (line 134 of ..theme.inc).

Issue #1081072 Must be able to save empty, non-required, multigroup, even if it contains required fields. Issue #522564 Remove empty groups even if not marked 'remove'.

Issue #1092044 Make sure all multigroup formats are preserved, even if not visible on the current tab.

#849420 Additional tweaks to nested fieldgroups so they work even if nested inside fieldsets not created by CCK. Also makes it possible to nest multigroups inside groups/fieldsets that are vertical tabs, so long as the multigroup itself is not a vertical tab.

#1008184 by merlinofchaos, bojanz, dereine, yched: Adapt to Views 3 "semantic views" feature (backwards compatible with Views 2)

#887742 - fix notices in _content_get_formatter() - happens in Views when a field is not present in the node type of the rendered row.

#863226 by KarenS, make sure we have a function that will return inactive instances when other instances of the same field are still active.

Revert #780566 by stella, add drupal_alter() for content_allowed_values lists created by userreference and nodereference, needs more thought.

#780566 by stella, add drupal_alter() for content_allowed_values lists created by userreference and nodereference.