Fix options for IE.
Patch sponsored by leftrightminds.com

I cleaned it up a little. No need to keep track of the index, just use push.

- Changed theme_activeselect() to use _form_set_class() instead of _form_get_class() (the latter function has been removed from Drupal core).
- #57929: use JSON instead of pipe delimiters for AJAX response text. Activeselect now uses drupal_to_js() (on the PHP end) and parseJson() (on the JS end) for response text, and this has allowed a large amount of pipe-parsing code to be removed from the Activeselect JS library. API.txt has been updated to reflect this, and category_activeselect() has been updated to use the new API.
- New activeselect_explode_values() function, which does the work of turning the request string into a PHP array. API.txt and category_activeselect() have been updated with this function.

- #56026: multiple parents not saved when using activeselect. Turned out that this problem could be solved entirely by patching activeselect, rather than by patching category (the Form API processes select data as an array if the name of the element has '[]' brackets on the end - so activeselect now appends and removes '[]' characters from a target element's name dynamically).
- Changed the activeselect API to use '|selected' notation, instead of the '#' notation, to indicate selected elements.

Changed the activeselect API, so that the 'multiple' attribute is defined more cleanly, at the end of the target name, rather than as a 'fake option element'.
Note: I experimented with various ways to solve #56026 purely by changing the JS, but was unsuccessful. It seems that a multi-select element with 'multiple="multiple"' defined, absolutely cannot be turned into a single-select, using JS (even removing it with removeAttribute() and removeAttributeNode() had no effect).

- #54050: move to new DB install system (category and all related modules).
- #54032: 'node type' DB field too short.

#53647: Fixed up IE problem with activeselect. Activeselect and category now working fine in IE. Also fixed help text in category_views.

Cascading activeselect now working much better in IE. However, no matter what I do, the whole activeselect thing completely stuffs up after the first page load in IE (doesn't work properly again until you close and re-open IE).

Recursive / cascading activeselect containers now working properly! Change the value of one activeselect, and it will trigger a change in another one, which will trigger another one, etc. This is the coolest thing EVER - I could play with it all day! Note: still buggy in IE6, but fine in FF.

- If a container is an allowed distant parent for any other container on the same node form, that container is displayed as an activeselect form element.
- Only categories with distant parents in the source container are affected, so it is possible for multiple activeselects to share the same target (not yet tested).
- Recursive / cascading activeselect containers are now possible (still a bit buggy).

- IE fixes: the width of the target select element now gets dynamically set (by altering its style.width attribute using JS), to stop IE from giving it a width of 0; and new options are created using 'new Option()' rather than 'appendChild()', because IE6 refuses to display option text if the latter method is used.
- Style sheet and throbber image (copied from core /misc directory) added.
- Throbber now works properly in FF (but not visible in IE).

Added support for changing a select box to single- or multi-select, and for remembering the originally selected element, using AJAX.