Ducktype no-parse fences and an actual spec

I've added no-parse fences to Ducktype. If you want to embed something
that would involve a lot of escaping, you can surround it with [[[ and
]]] to avoid escaping.

[code]
  [[[
  [You $don;t have to $es(cape) this weird stuff.
  ]]]

That's the literal text in there. If you wanted to write that without a
fence, it would look like this:

[code]
  $[You $$don;t have to $$es(cape) this weird stuff.

The opening [[[ has to start an indented line, but it can have content
after it. The closing ]]] has to be on a line by itself (maybe with
whitespace). As a special case, tho, you can do a one-liner:

[code]
  [[[[You $don;t have to $es(cape) this weird stuff.]]]

Also, I've finally actually pushed the incomplete Ducktype spec to the
projectmallard.org site:

http://projectmallard.org/ducktype/1.0/

It needs quite a bit more content. Examples and notes are probably
easier to contribute than the spec parts. And then we really ought to
get some tutorials under /about/learn/.

--
Shaun