Bump up Cython version
Docs: RSA padding modes were overzealous
Docs: rsa.Key.sign saltlen kwarg
Docs: Better explain RSA padding options
Docs: Fix rsa.Key.verify typo
doctest.IGNORE_EXCEPTION_DETAIL for Python 3
Docs: Restore exception details in doctests
Start testing OpenSSL RSA
Add rsa.Key.raw_* methods
Tests: verify signature from OpenSSL
Notes
Remove rsa.Key.raw_functions

They are already accessible via `padding='none'`.
rsa.Key.verify doesn't need a sig in raw mode
Improve utils docs and tests
Test sandbox is no longer dated
`cipher.aes(key, iv, mode)` works

Previously, this would supply mode as the `cipher`
arg when constructing the `Cipher` object.

Addresses part of issue #21.
ECB cipher throws ValueError with non-NULL IV

We wan't to force people to realize that the IV is
not doing anything.

Closes issue #21.
Don't pass *args from Descriptor.__call__ to Cipher

This makes it more obvious that there are
API differences.

See issue #21.
IV must be None for ECB, and non-None for others.

See issue #21.
Tiny cipher docs tweak