Issue #1081072 Imagefield validation does not use error_element, needs a tweak so that the empty required field gets highlighted correctly.

Issue #1081072 Imagefield validation requires that we alter the field_info values or it will still require an image in an empty group.

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).

- 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.

#766734 Restructure multigroup field layout to be consistent with other fieldgroups, and use content_get_nested_elements() to grab the right values no matter how the fields are structured.

#730154 Remove patch included in nested fieldgroups patch to try to force this error to show up so we can fix it.

#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.

#849420 by Roberto Gerola, rconstantine, thekevinday, ericduran, KarenS Add ability to nest fieldgroups within other fieldgroups.

#1008184 followup by dereine: Adapt to Views 3 "semantic views" feature (backwards compatible with Views 2)

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

followup fix for #736440 - prevent "Fatal error: __clone method called on non-object" reported in #988890