Version 2.6 includes OpenSSL no-engine support.

This also removes python-idna as a dependency. idna became optional with
version 2.5 (https://cryptography.io/en/latest/changelog/#v2-5).

This also updates the package title field and updates both Python 2 and
3 versions to use the same field.

Signed-off-by: Jeffery To <jeffery.to@gmail.com>