Whitespace fixes
Eliminate duplication in Vagrantfile

Cleaned up contribution from Geronimo Orozco, ignoring the
vagrant-hostmaster portion for the time being.
Update README with tested compatible OSes
Use the osfamily fact instead of operatingsystem
Ensure puppet-lint is installed on the master
Document the puppet-lint gem installation
Remove File defaults so code under test can use them

With this resource default in place, code under test which sets the
backup parameter on File cannot compile. It seems reasonable to kill the
backups here, since we're dealing with ephemeral vagrant boxes anyways.
Implement apt pinning for Debian-based hosts

This fixes installation of a specific version of Puppet on
Debian/Ubuntu. Apt gets confused trying to resolve dependencies for
Puppet packages without it.
Vagrant 1.1+ required
Vagrantfile adapted to Vagrant 1.1+
Fixed the deb lit to inclide the 'dependencies' repo since it is required to install puppet via apt.