args swapped in docs
Merge pull request #473 from ptone/patch-1

args swapped in docs
Revert "args swapped in docs"
Merge pull request #474 from GoogleCloudPlatform/revert-473-patch-1

Revert "args swapped in docs"
Merge pull request #444 from dhermes/implicit-dataset-from-environ

Implicit dataset from environ
Remove Key.from_path and derivative uses.

Addresses first part of #451. Also removes uses of path in
place of key since Key constructor will enable such easy
use going forward.