Normalize Travis-CI config w/my other Puppet projects

Including:
* Move sections to be the same order.
* Move varying sections to end for easier diffing.
* Test against Ruby 1.8.7, 1.9.3 and 2.0.0.
* Test against Puppet 2.7.x, 3.6.x and 3.x.x.
* Add test matrix, setting fast_finish, allowing failures for all Rubies but
  1.8.7 and excluding combination of Puppet 2.7 and Ruby 2.