No longer bundled with the library (as jquery-ui is bundled with the
main software, including the autocomplete part).
Rewrites had to be made to migrate, as several API things had changed
when jquery-ui took over the library.
Currently (like before, right?) this only autocompletes in the end of
the current textarea. So you can't jump back in the middle of a text
and autocomplete a user or group. This is a serious deficiency, though
not a regression.
lib/plugin.php now has a parent onAutoload function that finds most common
files that are used in plugins (actions, dataobjects, forms, libs etc.) if
they are put in the standardised directories ('actions', 'classes', 'forms',
'lib' and perhaps some others in the future).
