Merge pull request puppetlabs#254 from apenney/421

Prepare a 4.2.1 release.

Merge pull request puppetlabs#252 from hunner/release_4.2.0

Release - 4.2.0

version 4.1.0

version 4.0.2

version 4.0.1

version 4.0.0

version 3.2.0

version 2.6.0

version 3.1.1