don't ignore lint errors
move puppet-lint config back to Rakefile

You can't set 'ignore_paths' in .puppet-lint.rc and having config in two places
is confusing.
Rakefile: use Puppet Approved puppet-lint config
Merge pull request #522 from 3flex/puppet-lint

Update puppet-lint config
Merge pull request #521 from 3flex/remove-lint-ignores

don't ignore lint errors
travis: enable container-based builds

Jobs running on container-based infrastructure:
1. start up faster
2. allow the use of caches for public repositories
3. disallow the use of sudo, setuid and setgid executables

http://docs.travis-ci.com/user/workers/container-based-infrastructure/
Merge pull request #524 from 3flex/container-builds-on-travis

travis: enable container-based builds
Notify the service after purging configuration files
Merge pull request #525 from radford/notify-on-purge

Notify the service after purging configuration files