Version Control With Subversion Source

Patch from Larry Shatzer <Larry.Shatzer@...>.

* doc/book/book/appb.xml
Use <quote> where appropriate.
Use <command> around a svn command.

* doc/book/book/ch03.xml
* doc/book/book/ch06.xml
Use full subcommand name, not an alias.

* doc/book/book/ch07.xml
Use official subcommand name 'delete', not 'remove'.