Version Control With Subversion Source

* 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.

* COMMITTERS: Set up new Italian committers.

Book Spanish. Found translation for hash table.

Add comments to the website HTML delimiting a region for translations to
provide custom content related only to their translation.

Book Russian. Translated some paragraphs.