Implementing storage regression tests to match gcloud-node.

Not meant to be merged. Some missing features were
uncovered or hard to use APIs and I want to discuss here
and then map out the plan (i.e. how to break this up).
If we are trying to exercise the bucket's `upload_file` convenience method, we can't do that by handling explicit keys. :(  But I think handling keys is the "cleaner" solution.