Version Control With Subversion Source

cmdline options). This fixes issue #73.

* src/en/HACKING: Clarify our stance on option vs switch for --these
--things.

* src/en/book/ch00-preface.xml, src/en/book/ch09-reference.xml,
src/en/book/ch05-repository-admin.xml,
src/en/book/appb-svn-for-cvs-users.xml,
src/en/book/ch04-branching-and-merging.xml,
src/en/book/ch02-basic-usage.xml: s/switch/option/ where
appropriate.