[Fedora-spins] New spin-kickstarts practices for f20 / rawhide

When adding new ks files to spin-kickstarts you no longer have to edit Makefile.am. When you want to build a new spin kickstart package, you checkout the version of spin-kickstarts you want to use (use reset --hard if HEAD isn't going to be the latest commit). Tag the commit (don't forget to push the tag as tags aren't normally pushed by default). make will make the tar ball. make publish will scp the tar ball to the fedorahosted download area. Then checkout the fedora package spin-kickstarts. fedpkg new-sources the new tar ball. change the version and add a changelog entry to the spec file. fedpkg build fedora-install-fedora.ks now points to the rawhide repo in master. When f20 is branched it will point to fedora repos. The excludes have been moved off the repo commands, so when overriding the repos you don't need to include a bunch of excludes. When branching, the only two files that need to be changed (to adjust the repos) are fedora-install-fedora.ks and fedora-repo.ks.