Remove Support for Python 2.6

[mide]

This is a landing page for people to discuss the end of support of Python 2.6.

As of aws-google-auth version 0.0.16, there will be no support for Python 2.6. Feel free to check out the pull request (#38) for more information.

Contributing Factors:

• pip doesn't support 2.6 since fall 2016 Drop support for Python 2.6? pypa/pip#3955
• pytest doesn't support 2.6 since fall 2017 finally drop python2.6 support pytest-dev/pytest#2812
• setuptools doesn't support 2.6 since fall 2017 Drop support for Python 2.6 pypa/setuptools#878
• Many other tools look like they're moving in this direction (and eventually moving to remove all 2.* support, but we're not going that far yet.)

[mide]

I am closing as this ticket is purely acting as a landing page. The changes to remove support of Python 2.6 will occur when #38 gets merged.