Puppet & librarian-puppet version support

These changes should be simple enough to merge. Upon going back to the base version of loom, the first thing I found I wanted back was the ability to specify specific versions of puppet and librarian-puppet.

Additionally, placed a default hiera.yaml file for puppet >=3.0 support.

To set a specific version, place the following in `fabfile.py`
    `env.loom_puppet_version = "2.7.19"`
    `env.loom_librarian_version = "0.9.6"`