Added publishing of metadata files
Merge branch 'jconnor-new-yum-distributor' into jdob-nyd-metadata-publish

Conflicts:
	plugins/pulp_rpm/plugins/distributors/yum/publish.py
	plugins/test/unit/test_yum_distributor_publish.py
Merge pull request #387 from pulp/jdob-nyd-metadata-publish

Added publishing of metadata files.

Spoke with bcourt about this. At the same time this was written, some more generic pieces were written that could consolidate this a bit. He's going to take what's merged here and rework a bit with the new utility methods.