Changes: repo rename to resolve package naming conflict

Signed-off-by: Miroslav Safr <Miroslav.Safr@gmail.com>
Changes: -rs switch changed to -rp (resign packages), New:rpmrepo signing, update repo istead of recreating it

Signed-off-by: Miroslav Safr <Miroslav.Safr@gmail.com>
New: changelog-limit flag to speed up repo db creation

Signed-off-by: Miroslav Safr <Miroslav.Safr@gmail.com>
New: -rr, --recreate-repo flag to switch between recreating or updating repo (default is update)
Signed-off-by: Miroslav Safr <Miroslav.Safr@gmail.com>