Version Control With Subversion Source

More website updates.

* www/old-versions.html
Put 1.4 versions on this page, add Safari button, and tweak header line.

* www/index.en.html
Tweak Safari button destination URL and header line formatting.

* src/de/book/foreword.xml
* src/de/book/ch01-fundamental-concepts.xml
* src/de/book/ch02-basic-usage.xml
- Patch of Jens Seidel
- fixed typos.

* src/en/book/ORPHANED-TOPICS
Lose this -- we cover project layouts and importing in other places.

Update svnbook homepage to show tagged 1.5 version (among other things).

Prime book for 1.6 coverage.

Add en 1.5 placeholder directory.

Tag 1.5 version of the English book (also known "Version Control With
Subversion, second edition", or "ISBN 10: 0-596-51033-0", or "ISBN 13:
9780596510336", or "Pilato's Bane", or ...)

* ru/book/ch-advanced-topics.xml: translation for 'Peg and Operative Revisions' section
* ru/book/ch-customizing-svn.xml: chapter renamed because it had the same name with another chapter

* ru/book/ch-basic-usage.xml: spelling fixes
* ru/book/ch-branching-and-merging.xml: spelling fixes
* ru/book/ch-branching-and-merging.xml: new translation of some paragraphs and spelling fixes

The author of changes is Dmitry Bogomolov (g1itch at i.ua)

* ru/book/ch-advanced-topics.xml: fixes of stylistics