Version Control With Subversion Source

* src/en/book/appb.xml,
* src/en/book/ch00.xml,
* src/en/book/ch01.xml,
* src/en/book/ch02.xml,
* src/en/book/ch03.xml,
* src/en/book/ch04.xml,
* src/en/book/ch05.xml,
* src/en/book/ch06.xml,
* src/en/book/ch07.xml,
* src/en/book/ch08.xml,
* src/en/book/ch09.xml
In a bid for "change which matters the least", consistify our commented
out visual horizontal rules for <sect1> and <sect2> sections, dropping
the section names and numbers from those altogether.