Version Control With Subversion Source

the way to content complete, then I'll start making refining passes.

*** This should build without errors ***

* src/en/book/ch-basic-usage.xml: Almost content complete (but not
reviewed for coherence or clarity).

* src/en/book/ch-reference.xml, src/en/book/ch-advanced-topics.xml,
src/en/book/ch-repository-admin.xml,
src/en/book/app-svn-for-cvs-users.xml,
src/en/book/app-quickstart.xml: Update xrefs