Split ajaxCategories away from core for now, into an extension:

Split ajaxCategories away from core for now, into an extension:

* Move js/css/images from core into extension dir (kept svn history in tact)

* Removed from core:
** Messages
** Resource definition
** Default settings

* Recreated in extension:
** Messages with 'inlinecategorizer' prefix (instead of generic 'ajax' prefix).
** wgResourceModule definition
** Hooks for adding module to the page
** Setting wgAJAXCategoriesNamespaces kept (renamed to $wgInlineCategorizerNamespaces)

* Made minor adjustments to the messages:
** Fixed references to other messages (in /qqq) with the new message key

* Made minor adjustments to the javascript:
** Usage of mw.msg fixed to the new message keys
** Removed "@since 1.19"
** Removed "Relies on mw.user.getId" (because it didn't', and still doesn't)
** Object 'mw.ajaxCategories' -> 'mw.InlineCategorizer' (capitalized, since it's a constructor, per our conventions)
** Removed 'disableAJAXCategories' config, not needed.

Summary of justification for move out of core (again):
* Too many issues with the parsing logic (many cases still don't work yet)
* Almost untested and untestable because of mixing UI with logic code. Needs separation.
* See http://www.mediawiki.org/wiki/User:Krinkle/Extension_review/InlineCategorizer#Prequel

One day we might move it in, or if the "new parser" is ready and the "visual editor" we might not need it all together and it'd simply be a 10-20 line module in the visual editor (that, or it'd be part of the visual editor by default).

Anyway, I'm not against this module. if we can get this to an acceptable state soonish before any of the new parser / visual editor is ready, then I see no problem in bundling it with core and/or merging it into core.