I am not a fan of the order of this (setting the `ENV` var before the `require`) but it is required because of the parse-order of checking environment variables. I wish rspec had a way of taking command-line options.

But two ideas:
1) this is backwards-compatible with rspec-system and will aid people in migration without changing their whole world.
2) Beaker can take command line options, and could eventually take a `--rspec` option when all this settles down and starts going into beaker. (I haven't thought too much about if/how this would look though.)