python-cryptography: new package (closes #2035)

python-cryptography: new package (closes #2035)

From the README:

cryptography is a package which provides cryptographic recipes and
primitives to Python developers.  Our goal is for it to be your "cryptographic
standard library". It supports Python 2.6-2.7, Python 3.3+, and PyPy 2.6+.

This depends on python-cffi host install (#2034)

Signed-off-by: Jeffery To <jeffery.to@gmail.com>
[Squashed update to latest upstream version into this introducing commit]

Signed-off-by: Michael Heimpold <mhei@heimpold.de>