CFT: adding configuration file support to pkg_install

[Florent Thoumie]

This adds support for /etc/pkg.conf configuration file.
Also, this adds support for naive multi-site package fetching.

Any comment welcome (and appreciated).

Patch is here: http://people.freebsd.org/~flz/local/ports/pkg-install-config.diff
Tarball is here:
http://people.freebsd.org/~flz/local/ports/pkg-install-0a553aac.tar.bz2

-- 
Florent Thoumie
flz at FreeBSD.org
FreeBSD Committer