Use full download link instead of just file name

Enables us to later read the URL from the .spec file instead of
having it available somewhere else.
Provide script to create source packages

This script will parse the .spec files for URLs to download and patches
to apply, and setup a build directory from which source RPMs can be
created.
Merge pull request #1 from rolk/001_srpms

Read download URL from the .spec files themselves