Log Message:
Update editors/xemacs-packages to the latest and greatest.

These were release candidates according to upstream (Stephen
Turnbull):

"Right now, everything has gotten all the beta testing it's going to
get, so you can just package it from experimental."
<http://xemacs-beta.xemacs.narkive.com/TgII9kK7/when-do-experimental-packages-turn-stable>

but did not make to final before xemacs.org went south.

In addition, teach the update mechanism to use a configurable ftp
server.