Use puppetlabs yum repos

We want to pull int he latest released version of facter, not the slightly
outdated one from the Fedora repos.

Fixes https://github.com/puppetlabs/razor-el-mk/issues/12
* Gemfile.lock: no functional change; use what bundler produces for me
* build-livecd-root: script for the parts of building the MK that run as root
* sign-microkernel: script to add a SHA256SUM.sig to a MK tarball
* razor-el-mk.gemspec: bump version to 0.0.2