Change remove_image to check if image is a dictionary and use Id value if it is.
Remove trailing whitespace.
Merge pull request #333 from alexliew/change_remove_image

Change remove_image to check if image is a dictionary.
Changed assertIn to assertTrue(... in ...) (2.6 support)
Merge branch 'master' of github.com:dotcloud/docker-py
Merge branch 'master' into 0.6.0-release