Added PEMSerializationBackend interface
Merge branch 'master' into pem-loading-backend
Document the new interface
Merge branch 'master' into pem-loading-backend
typo fix
Merge pull request #1276 from alex/pem-loading-backend

Added PEMSerializationBackend interface
Start moving everything to the new API
fixes
Explicitly deprecate these as well
remove duplicate argument
multibacken for docs
Try a different phrasing
Grammar from @reaperhulk
Merge pull request #1326 from alex/pem-serialization-backend

Start moving everything to the new API
Implemented support for loading EC private keys

Loads Elliptic Curve private keys from .PEM files, whether encrypted or
unencrypted, given that the encryption method is supported. Also included
changes to the test files and documentation for said method.
Fix two bugs with CommonCrypto GCM that can result in invalid output.

Bug #1: Call to AAD but no call to update. Get null tag bytes.
Bug #2: Call to update without call to AAD. Get null ciphertext bytes.

Fixes #1329
byte strings are byte strings
moved GCM tests to be run against all backends, added radar bug numbers
Adjusted formatting and added EC check

Due to the code failing the PEP-8 test, the test code has been reformatted
so that there are two blank lines between the function and the next class,
and the overlong line has been adjusted. Also added a check to the private
key loading function to check for the Cryptography_HAS_EC field. This has
been tested on Windows only.
Corrected formatting

Line was too long in ./cryptography/hazmat/backends/openssl/backend.py, so
moved the second part of the statement onto a new line using \