The location of Puppet::Util[::Execution].withenv changed from Puppet 2.x to 3.x
Merge pull request #86 from sodabrew/puppet_util_withenv

Correct use of withenv
Travis should run three Puppet versions in a matrix with three Ruby versions, but limit Puppet 2.6.x to Ruby 1.8.7.
Merge pull request #85 from sodabrew/travis_puppet_version

Try to get Travis to respect the three different puppet versions