* Fix root-mode. Currently, few plugins support it, and I know the
  installer and capplets don't.

*DONE* Auto-detect non-metatheme-installed themes, for those that can
  do so, like gtk and sawfish.

* Gtk plugin needs to not call gtk-config. I think it only calls it for
  is_root though, so we're safe for now.

* Fix capplet's updater call to be non-blocking.

*DONE* * Add alternate clist-based theme selector

*DONE* * Add capplet support for uninstallation. This requires changes to the
  theme installation procedure (It would have to record lists of
  what themes an ext is used by).

*DONE* Go through and mark up all the translatable strings.

*DONE* * Add a virtual method to ExtHandler to retrieve readable argument names
  from a subclass.

*DONE* * Add theme saving/creation support from the capplet. This might involve
  changing the installer to register default urls associated with exts.

* On that note, fix up ext-info to support generic http and ftp urls, and
  to try to figure out the file sizes without needing the rdf.

* Give nicer errors on invalid URLs/not finding a theme on themes.org. For
  the latter, it currently considers it to simply not need an update. This
  behavior may be unavoidable.

* Add a "verify URL" button to metatheme-edit. This would require moving
  ext-info somewhere else, maybe.