libz: update the upgrade instructions to reflect reality

Move contrib/zlib to sys/contrib/zlib so that we can use it in kernel.
This is a prerequisite of unifying kernel zlib instances.

Submitted by: Yoshihiro Ota <ota at j.email.ne.jp>
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20191

Fix up FreeBSD tag for files not from a vendor branch

Unexpand the tag, remove the fbsd:nokeywords property and add the
svn:keywords property. This should eliminate the gratuituous diffs
that appear on these files in projects branches.

Sponsored by: The FreeBSD Foundation

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

- Import the HEAD csup code which is the basis for the cvsmode work.

Document zlib update procedure and provide future maintainers a
snapshot of the current state of the import.

MFC after: 2 weeks