Add a cnucnu based fetcher

The cnucnu based fetcher can pull versions frm any HTTP Url.
The URL can be passed to the fetcher using the branch name.

Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>
repoquery: Option to allow dupes

Sometimes dupes in a repo are okay, i.e. when it's a multiarch repo
having one build for each arch.

The squash_dupes option now squashes duplicate lines of repoquery into
one.

Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>
examples: Add ovirt example (including cnucnu)

Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>