Version Control With Subversion Source

The readme.txt spoke of changes to the DocBook XSL to output UTF-8, but now
we have shifted from html to xhtml, UTF-8 is the default anyway.
The book XML files were just a plain untouched copy of the English book - but
manually copied and "svn add"-ed, not actually "svn copy"-ed!
There has been no contact with the translators for some time, and if they come
back, we should set up a new ru/ directory that is properly copied.

* ru/: Delete.