Reorder SendToBackpackRequest arguments in env.js to match implementation
Made acceptance tests use real SendToBackpackRequest and
SendToBackpackRequest.Group objects. This involved upgrading
the acceptance test notion of badges to urls backed by actual
badgehost assertions, as well as enhancing the internal
FakeBackpack class.

Also added some more detailed assertions to a few step definitions.
Merge pull request #1 from stenington/cucumber

Acceptance tests now use our "real" SendToBackpackRequest and SendToBackpackRequest.Group implementations.