Resolved test suite problem with Ruby 2.0.0
* Ruby 2.0.0 changed the default script encoding from US-ASCII (as far
  as I can tell) to UTF-8.  A side effect of this is that it breaks one
  of the tests that assumes that a literal string will be in a specific
  encoding.  This was resolved by using force_encoding.
* This should resolve all the outstanding issues with the test suite
  under Ruby 2.0.0 (and I hope 2.1.0), so the .travis.yml file was
  updated to reflect this.