#296765: user autocomplete incorrectly required administer views access. Also incorrectly required Views UI module.

Some refactoring of how handlers are handled, particularly with their default options. This is an unfortunately widespread change and will affect modules utilizing the API.

Redo some form stuff to make it easier to choose the next form when chaining; and add some new chaining options. This commit will require you to visit admin/build/modules to reset the menu or the UI will stop working.

Retooled the form replacements into a single, unified form builder (which may be suitable for use in Drupal 7)

Add better hiliting to the UI; now possible to tell what items are overridden as well as what item is currently being edited

Checkpoint checking. UI is getting better, but it is also getting further away from what currently runs, so when this is done a bunch of refactoring is going to have to happen.