Make puppet-lint warnings failures

We have most of the annoying puppet-lint checks disabled so we'll turn warnings
into failures so that Travis-CI properly informs us of issues.
Fix puppet-lint warnings
Merge pull request #370 from sdodson/fail_on_puppet_lint_warnings

Make puppet-lint warnings failures
Version 4.1.2

Includes changing license field to 'Apache-2.0' and bumping stdlib
requirement to ensure proper installation in Puppet Enterprise.