Version Control With Subversion Source

Fix (I hope) issue #110 ("HTML version fails to load correctly").

* src/en/book/images/draft.png
New file, apparently required by XSLT template sets which refer to
'images/draft.png' rather than to the canonical web-located image.

Finish issue #25 ("Blocking Merge Unaware Clients").

* src/en/book/ch04-branching-and-merging.xml
(svn.branchmerge.advanced.pre1.5clients): Give a sample start-commit
hook script which blocks commits from merge-tracking-unaware
clients.

* src/en/book/ch09-reference.xml
Oops! Syntax error fix.

* src/en/book/ch05-repository-admin.xml
Quick! Fix a typo before Richard Cavell finds it! ;-)

Finish (as far as I can tell, at least) issue #19 ("Changes to copy
behavior in 1.6").

* src/en/book/ch04-branching-and-merging.xml
(svn.branchmerge.advanced.finalword): Remove note about mergeinfo
appearing as a result of a copy or move.

* src/en/book/ch04-branching-and-merging.xml
(svn.branchmerge.using.create): Tighten up the scope of "every file
and subdirectory" a bit.

Suggested by: Neil Brown <neilx.d.brown@...>
(Tweaked by me.)

* src/en/book/ch03-advanced-topics.xml
Minor wording tweak.

Patch by: Richard Cavell <richardcavell@...>
(Tweaked by me.)

Finish issue #27 ("1.6 change: '--set-depth exclude' support").

* src/en/book/ch03-advanced-topics.xml
(svn.advanced.sparsedirs): Document the new --set-depth exclude
option, and provide an example of its use.

* src/en/book/ch09-reference.xml
(svn.ref.svn.sw): Note the 'exclude' value for --set-depth.
(svn.ref.svn.c.switch, svn.ref.svn.c.update): Remove the note about
not being able to de-telescope a working copy.

* src/en/HACKING,
* src/en/book/appa-quickstart.xml,
* src/en/book/appb-svn-for-cvs-users.xml,
* src/en/book/appc-webdav.xml,
* src/en/book/ch00-preface.xml,
* src/en/book/ch01-fundamental-concepts.xml,
* src/en/book/ch02-basic-usage.xml,
* src/en/book/ch03-advanced-topics.xml,
* src/en/book/ch04-branching-and-merging.xml,
* src/en/book/ch05-repository-admin.xml,
* src/en/book/ch06-server-configuration.xml,
* src/en/book/ch07-customizing-svn.xml,
* src/en/book/ch08-embedding-svn.xml,
* src/en/book/ch09-reference.xml
Embed <footnote>'s into the primary text without spurious line breaks now.

Finish issue #52 ("Explain the differing ways in which -rX is
interpreted in externals definitions").

* src/en/book/ch03-advanced-topics.xml
(svn.advanced.externals): Note the -rN is a peg revision in the
pre-1.5 externals definition syntax and an operative revision in the
newer syntax.