[RFC] doc directory reorganisation & I18N

[Ian Clatworthy]

It's rubber-hits-the-road time now for changing the organisation of
documentation within our source tree. The feedback on the documents I
want to see has been positive so I'm planning to proceed on the
assumption that everyone is happy enough with the proposed outcome, i.e.
 "Current Documentation" in the new look
http://bazaar-vcs.org/Documentation.

Here's what I'm suggesting w.r.t. layout under our 'doc' directory:

index.txt
developers/   (as now)
  index.txt
  ...
en/
  index.txt
  mini-tutorial/
  quick-reference/
  user-guide/
    (most of the existing docs)
  user-reference/
  switcher-guides/
  migration-guide/
  release-notes/
  developer-guide/
xx/
  (subset of en tree reflecting what has been translated)

Highlighting the main points:

1. We put a structure in place now to support multiple languages
2. As a rule, 1 directory per document (or theme) below that
3. existing developer stuff stays where it is now
4. For English, the doc build process will copy and/or generate the
   content for some documents, namely:
   * embedded help -> user-reference (as agreed previously)
   * NEWS -> release-notes
   * selected stuff from developers/ -> developer-guide
5. For non-English, translations of one or more docs can be maintained
   directly within the tree, including translations of the generated
   content (user-reference, release-notes, developer-guide).
6. The whole tree below doc/ can be pushed to doc.bazaar-vcs.org/nnnn
   and that website will have comprehensive docs for each release in
   one or more languages.

Does this sound good to everyone? If not, please suggest what you'd like
to see instead.

Thanks,
Ian C.