It's not required anymore:
All tests pass, as before.
Removed lib/arel/sql/engine.rb because it's not required anymore.
Merge remote-tracking branch 'rails/master'
Borked the tests, so I'm reverting for now.
Revert "Merge pull request #81 from parndt/master"
This reverts commit f3214d9, reversing
changes made to fc787a4.