[MLton] MLton wiki

[Stephen Weeks]

In preparation for moving wiki.mlton.org to www.mlton.org I've cleaned
up the wiki and httpd.conf so that wiki.mlton.org URLs behave as much
like www.mlton.org URLs as possible. 

Please try out old-style URLs and report any problems.

I've added appropriate redirects (like history.html -> History).  I
turned on wiki support for file attachments, and used those in places
(Download, Experimental, Developers, ...) to replace links leading
outside the wiki (into www.mlton.org) with links into the wiki.

There still remains some links in the wiki that point outside:

* changelog	/changelog
* commitlog	/commitlog
* CVS		/cvs/
* Mailing lists /mailman/
* User Guide	/user-guide/

These are all handled by appropriate Aliases, Redirects, or
ScriptAliases in httpd.conf.

changelog and commitlog could be maintained as attachments on an
appropriate page, but it's not clear to me which one, so I've left
them alone for now.

CVS and mailing lists will remain as ScriptAliases pointing to the
appropriate tools (MailMan, ViewCVS).

The User Guide will remain in HTML external to the wiki for the
foreseeable future.  It is a long-term project to convert the User
Guide into wiki format, and I'm not even sure if we should do so.  I
don't know how much people like to have the pdf format and to be able
to download the gzipped html.  We need to come up with some reasonable
alternative before switching.  It would be nice to have a way to
extract printable documentation from a subset of the wiki, as well as
a way to gzip part of the wiki for offline viewing.  There is also the
issue of version skew -- it is quite nice to have a snapshot of the
user guide (html and pdf) associated with each release.

I don't think these problems apply nearly as much to the Hacker Guide
and the Style Guide, so we should proceed with those on the wiki.