3.2.0

List of PRs / issues for this release

Features

• Generators returned by attach(), logs() and events() now have a
  cancel() method to let consumers stop the iteration client-side.
• build() methods can now handle Dockerfiles supplied outside of the
  build context.
• Added sparse argument to DockerClient.containers.list()
• Added isolation parameter to build() methods.
• Added close() method to DockerClient
• Added APIClient.inspect_distribution() method and
  DockerClient.images.get_registry_data()
  • The latter returns an instance of the new RegistryData class