user-manual patches

Since Johannes Schindelin said he'd be offline I thought I'd go ahead
and pick up his source code overview for the user manual.  I tried to
address your comments in a subsequent patch.

Also rework some of the glossary definitions, start moving some of
Documentation/howto into the manual, revise the preface a little, and
move the quick-start to an appendix.

Also available in the maint branch of my git repo:

	git://linux-nfs.org/~bfields/git.git maint

--b.