Sanitize create_container input

Client.create_container takes a volumes_from argument that should be: a
string, a list of strings, or None. If an empty list or dict is passed
instead, the docker daemon returns a 406 Client Error: Not Acceptable
Add test to check for the absence of volumes_from
Missed empty line for flake8
From api 1.10 dns and volumes should be transmitted to start()
fixes #175, fix flake8 erros
Merge pull request #203 from wallnerryan/issue-175

Add support for read-only bind-mounts (fixes #175)
Added ability to specify the full build context
Error with headers being NoneType
Fix for pep8 failures
Added test for gzip compressed tar
Relative 'errors' imports, for consistency
Merge pull request #198 from fcoelho/fix-volumes-from

Sanitize create_container input for volumes_from
Merge pull request #211 from aanand/relative-errors-imports

Relative 'errors' imports, for consistency
Re-format if/else
Line to long...
Do not ignore falsy values

If user pass empty strings or empty lists,
the deprecation policy will be ignored.

Check instead if those arguments are not the default.
raise instead of warn

because user must know its code will not behave as expected
if used against version >= v1.10.
Warn if user is using argument that will be ignored
Update documentation to reflect modification for `dns` and `volumes_from`
volumes_from is now a list from v.1.10