Fixed integration tests

Allow for pull as an option to docker build

Signed-off-by: Derek Hammer <derek.r.hammer@gmail.com>

Expand registry URL before login.

Enforce passing string as version param in ctor

Merge branch 'fix-env-variables-unicode' of github.com:maxcnunes/docker-py into maxcnunes-fix-env-variables-unicode

Fix expand_registry_url to be consistent with docker client.

In docker-py's auth.py the functions 'resolve_repository_name' and 'expand_registry_url' work together to result a hostname prefix to a base URL suitable for interaction as a Docker registry.

For example, "docker push foo.com/bar/baz" would try to resolve the hostname "foo.com".

These functions loosely correlate to 'ResolveRepositoryName' and 'newEndpoint' in the docker client code, respectively.

You can see from their implementations:
 - ResolveRepositoryName: https://github.com/docker/docker/blob/master/registry/registry.go#L191
 - newEndpoint: https://github.com/docker/docker/blob/master/registry/endpoint.go#L71

that neither of them appends 'v1' to the hostname during resolution.

This change simply removes the 'v1' suffix from these code paths, which enables docker-py to authenticate against private registries with which the docker client can already.

Allow ExtraHosts to be specified when creating a container

Walk file tree in order for deterministic builds

Python's `os.walk` does not order the lists of files and directories it returns, so in order to produce a consistent build context tarfile, they should be ordered.

Release 0.6.0

Change remove_image to check if image is a dictionary.

Conflicts:
	docker/utils/__init__.py
	docker/utils/utils.py
	tests/utils_test.py

Make history() return json.