Version Control With Subversion Source

* en/book/ref-svnmucc.xml
Add part intro.

* en/book/ref-svnlook.xml
Remove line breaks from the options list terms. They render ugly.

* en/book/ref-svndumpfilter.xml,
* en/book/ref-svnlook.xml
Indentation/whitespace/comment tweaks only.

* en/book/ref-svnadmin.xml
Fix indentation/whitespace/comments.

* en/book/ref-reposhooks.xml
Fix indentation/whitespace/comments.

* en/book/ref-reposhooks.xml
Add part intro.

Follow-up to r4420 with some clarifications and tweaks.

* en/book/ch05-repository-admin.xml
(svn.reposadmin.hooks.configuration): Tweak example to use string
substitution syntax, and call out that syntax in a <note>.
(svn.reposadmin.hooks.uses): Avoid introducing 'transaction
properties' as a standalone term. Mention backup/replication as
common uses. Drop (with a TODO left behind) the example of
ephemeral txnprop checking -- I can't even convince my*self* that
it's useful.

Some wording changes. Translated caveats.

Finish issue 178 ("document ephemeral txnprops (new in 1.8) and how
hook scripts might use them.")

* en/book/ch03-advanced-topics.xml
Move ephemeral txnprops stuff to Chapter 5.

* en/book/ch05-repository-admin.xml
(svn.reposadmin.hooks): Was svn.reposadmin.create.hooks. Completely
rework this section to give some more useful examples of
implementing hook scripts. Include hereing an example of checking
ephemeral transaction properties, and move the (short) list of
such props here from Chapter 3.

* en/book/ch04-branching-and-merging.xml,
* en/book/ch06-server-configuration.xml,
* en/book/ch08-embedding-svn.xml,
* en/book/ref-svn.xml
Update cross-references.

* en/HACKING
Note that we're using DocBook 4.5, and add a section describing how
(and when) index terms are marked up.