feat: Update to cryptography 1.9

versions of cryptography < 1.9 have had several compilation errors.
We should switch to a more recent version to allow for packages to
update.

closes #38

Author: jrconlin

python/setup.py

@@ -27,7 +27,7 @@
     ],
     keywords='crypto http',
     install_requires=[
-        'cryptography~=1.8.1',
+        'cryptography~=1.9',
     ],
     tests_require=[
         'nose',