Version Control With Subversion Source

More major changes to chapter 6.

* src/en/ch-server-configuration.xml:

- mention OSX keychain intergration
- more clearly delineate the ways to start svnserve
- explain how to run svnserve as native Windows Service
- reorganize 'extras' Apache section into clearer subsection
- document SVNListParentPath
- remind users to set svn:mime-type for better browsing
- document high-level logging feature
- lots of misc. cleanup & rewording

* src/en/book/foreword.xml
(Foreword): Correct verb tense, due to change in employement of two
out of three authors.

Fix some XML validation problems.

Major changes/additions to chapter 6.

(Still more to do, but this is a good start.)

* src/en/ch-server-configuration.xml:

- new Overview section which describes pros/cons of servers
- new Overview section which makes explicit server recommendations
- lose a couple of obsolete-ish sidebars
- factorize path-based-authz description into its own section,
and make other the two server sections point to it
- new best-practice sidebar recommending not to use
path-based-authz unless absolutely necessary.

Team component update

* www/index.en.html: Label nightly build as 1.4, not 1.3.

Be explicitly about externals definitions pointing at directories.

Suggested by: Eric Hanchrow <offby1@...>.

* src/en/book/ch-advanced-topics.xml
s/object/directory/ when talking about externals targets.

* src/tools/fo-stylesheet.xsl
* src/tools/html-stylesheet.xsl
Rearrange the order of some stuff in the stylesheets, because for
whatever reason it means the difference between a failed or a
successful built on my box.

Populate basic index entries for portions of the Reference chapter (it was
just too easy).

* src/tools/html-stylesheet.xsl
* src/tools/fo-stylesheet.xsl
Because I'm tired of looking this up repeatedly, put comments in the
stylesheets which point to the official HTML-rendered versions of the
parameter reference documentation.