Add port of the PC-BSD installer, pc-sysinstall.

pc-sysinstall is a new installer for FreeBSD, with a number of advantages
over the legacy sysinstall installer.

The port makes pc-sysinstall more widely available. It can be used with older
FreeBSD releases, with an appropriate conversion script. It has been used
to perform network installs of FreeBSD 8.3 in a university protocol testbed.

Josh Paetzel will be maintainer.

Submitted by:	bms
Reviewed by:	eadler