Spec that Que.stop! doesn't mistakenly commit transactions in ActiveRecord and Sequel. Specs occasionally hang, though.
Fix some intermittent spec hangs.
Merge branch 'master' into orm-transaction-specs
Simplify Worker a bit, and eliminate race conditions from wrapped exceptions.
Make Que.stop! more reliable on Rubinius.
Have Que.stop! also clean up workers. Doesn't matter for a closing process, but it does for our specs.