Version Control With Subversion Source

* en/book/ch04-branching-and-merging.xml:
Chapter-wide tweaks to reflect the fact the the current
release will be 1.8, not 1.7, when this version of the
book is branched.

* en/book/ch09-reference.xml
(svn.ref.svn.c.merge): Update 'svn merge' reference to
correspond to 1.8 behavior.

* en/book/ch09-reference.xml
(svn.ref.svn.c.mergeinfo): Update 'svn mergeinfo' reference to
correspond to 1.8 behavior.

* en/book/ch04-branching-and-merging.xml
Rework the Vendor Branches section, dropping all discussion of
svn_load_dirs.pl. I'm totally unhappy with the approach here, but I
don't want to lose the writing I've done so far. So ... this is
temporary. See https://code.google.com/p/svnbook/issues/detail?id=182
for the planned next steps.

Some minor tweaks, by way of follow-up to r4351.

* en/book/ch03-advanced-topics.xml
Add a warning about not supplying a log message on the svnmucc
command line.

* en/book/ch09-reference.xml
Add a missing "-v" argument to an 'svn log' example which obviously
used it.

Suggested by: danielsh

Merge r4352 from ^/trunk/en ("Document SVN_ASP_DOT_NET_HACK").

Merge r4352 from ^/trunk/en ("Document SVN_ASP_DOT_NET_HACK").

Finish issue 1 (!!) ("Document SVN_ASP_DOT_NET_HACK variable").

* en/book/ch01-fundamental-concepts.xml
(svn.basic.in-action.wc): Document SVN_ASP_DOT_NET_HACK.

Finish issue 5 ("Document svnmucc").

* en/book/ch09-reference.xml
(svn.ref.svnmucc.re.examples): Flesh out this section.

* en/book/ch03-advanced-topics.xml
(svn.advanced.working-without-a-wc.svnmucc): Add some missing -m
options to svnmucc command lines.