by Dave Reid: Do not vertical-tabify any fieldsets that do not have #group defined. This completely matches the D7 implementation.

by Dave Reid: Added support for the #group property in fieldsets to allow modules to define if a fieldset should be tabified by default.

by Dave Reid: Moved core JavaScript summary support into their own files so they can be easily overridden.

by Dave Reid: Add vertical tabs to block settings by default and re-sort form since alternations happen in pre-render.

by Dave Reid: Do not cache forms with vertical tabs on them since they might lose JavaScript on validation errors.

#644790 by Dave Reid: Simplify the module and integrate with form_controller for any customizations.

#444378 by dww, KarenS, quicksketch | Dave Reid: Fixed node form fieldsets not using proper CCK re-ordered weights by adding Vertical Tabs in #pre_render.

#478078 by neochief: Fixed erroneous revision summary when user does not have access to the create new revision checkbox.