Babel doc update

[Andrew Plotkin]

I'm getting around to a spec update which has been in the air for a while.
It's in the form of Github PRs right now:

https://github.com/iftechfoundation/ifarchive-if-specs/pull/18/files

This adopts the idea that any unrecognized file format, including
executables and text files, can use the "UUID://...//" byte sequence
convention to indicate an IFID.

This seems like an obvious addition. In fact it's so obvious that I keep
telling people to do it on the forum, and then remembering that it's not
actually part of the spec. Time to fix this.

I've also rearranged the doc to read a bit more smoothly. It now explains
all the *current* IFID schemes before getting into the *legacy* IFID
schemes.

I also have an update for the Babel tool which checks for "UUID://...//"
in unrecognized file types:

https://github.com/iftechfoundation/babel-tool/pull/35

The full text with this revision can be read here:

https://babel.ifarchive.org/babel_rev12-draft.html

I've also pulled the static Babel site, *minus* the spec itself, into this
repo:

https://github.com/iftechfoundation/babel-static

Dan Fabulich suggested this. The site index doesn't change much, but we
might as well have a repository for it.

Also, while going over the site, I set up a symlink

https://babel.ifarchive.org/babel.html

This will always point to the current revision of the spec.

--Z

--
"And Aholibamah bare Jeush, and Jaalam, and Korah: these were the borogoves..."
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