[CentOS] Yum priorities plugin

Hi All,

I have put the priorities plugin online at:

http://danieldk.org/code/yum/

This plugin allows you to associate priorities to repositories. Packages
from high-priority repositories are protected from being upgraded with
packages from low-priority repositories. Instructions can be found in
the README file, read the part about "check_obsoletes" with care. Please
keep in mind that this is mostly untested and thus beta code. Have fun!

-- Daniel