Remove auto-downloads.

[jashkenas]

Currently, if you pass a url as the input to a CloudCrowd action, the action will download the resource at the url before the action starts processing, and provide a handle to you as input_path. It's been suggested that this auto-download behavior is more unexpected than a real convenience. It would be a good idea to remove input_path and friends, and simply provide download for you to download a remote url into the action's temporary directory.