Version Control With Subversion Source

from the ora-2e-reorg branch. Which is long gone, but we have a time
machine available.

* src/nb/book/ch-introduction.xml
(svn.intro.whatis, svn.intro.history, svn.intro.features,
svn.intro.architecture, svn.intro.components): Moved to
ch-preface.xml.

* src/nb/book/ch-preface.xml
(svn.intro.whatis) Moved from ch-introduction.xml.
(svn.intro.history, svn.intro.features, svn.intro.architecture,
svn.components): Moved from ch-introduction.xml as sect2’s under
svn.intro.whatis.

* src/nb/LAST_UPDATED
Updated by "make sync HEAD=2570".