Fixed a bug in padding, and also made it more constant time
py3k fix
flake8 fixes
More constant time, better
Merge branch 'master' into padding-fixes

Conflicts:
	cryptography/hazmat/primitives/padding.py
Move all unpadding logic to C
Fixed flake8 issues
const correctness
Even more constant time
Make this comment more accurate
Use types more precisely
Move register so it can be used by cryptography.hazmat.bindings.interfaces.
flesh out method definitions.
Change interface names to fit in the new smaller interface surface and
correct method names on interfaces.
Start documenting the backend interfaces.
Remove unused include
de-opaque EVP_CIPHER_CTX a bit
Fix usages of interfaces.register
Document backend interfaces.
Merge pull request #267 from reaperhulk/evp-cipher-ctx-struct

de-opaque EVP_CIPHER_CTX a bit