Remove future from dependencies

[frenzymadness]

Resolves #115

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[a-detiste]

Please also remove all these useless Python2 definitions:

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

[frenzymadness]

Please also remove all these useless Python2 definitions:

Done.