Version Control With Subversion Source

* www/index.pt_BR.html
Reflect changes from index.en.html in r2049 and move existing
translation note to the newly created special region for
translation notes (see r2079).

* book/ch07.xml
(svn:eol-style): Fix typo. Put term 'operating system' in plural form.

* www/index.nb.html: Add a <base href> element to make remote editing of
the file more realistic.

Sync the Norwegian and English web page.

* www/index.nb.html: Updated r2054:2087 from index.en.html .

* www/index.en.html: Update the front page to mention downloadable tarballs.
Also correct some sizes.

Propagate HTML archive support.

* src/tools/book-dist.py
* src/tools/build-nightlies

Implement HTML tarball creation targets.

* src/tools/Makefile.base-vars
(ARCH_CMD, ARCH_EXT, HTML_ARCH_BASENAME, HTML_CHUNK_ARCH_BASENAME,
HTML_ARCH_TARGET, HTML_CHUNK_ARCH_TARGET): New variables.

* src/tools/Makefile.base-rules
(html-arch, html-chunk-arch, install-html-arch, install-html-chunk-arch):
New targets.
(clean): Adjust.

* src/tools/build-nightlies: Remove redundant 'import os.path'.
Remove 'import string', and convert only use of legacy string module to
modern form.
Tighten regions which run with a changed working directory, and handle
reversion to the initial working directory more rigourously, so that
relative paths function correctly as arguments.

Book Spanish. Translated four paragraphs.

Book Spanish. Relocalizar wasn the correct meaning.