I'd like to keep Twig compatible with Ruby 1.8.7, which is why it doesn't use Ruby 1.9's `require_relative` yet. We can look into using the [`require_relative` gem](http://steveklabnik.github.com/require_relative/) in a separate branch, though, to slim this one down.

The Ruby 1.8.7 support requirement is tucked away at the bottom of README.md, but I'll make it more obvious for the future.