commoncrypto initial backend
commoncrypto backend docs
simpler method of importing CommonCrypto backend into _ALL_BACKENDS
Merge branch 'master' into common-crypto-backend

* master:
  Use pytest.fixture for backends
  drop to >= 0.8 to make pypy happy
  change to anonymous enum
  require cffi >= 0.8.1
  remove extraneous spaces
  add hmac to commoncrypto binding
  bytes byte back
  add check to confirm we've loaded error strings
  Bind all the PEM errors
  Spelling!
  oops, bytes plz
  don't leak a context in the test
  add tests to the openssl backend to verify that we've registered
  Nonsense I think we need.
  This is a dep
  init the ssl library in the backend
  Actuall install a thing
  Try to run the spellchecker on travis
  Use a normal quote here, not sure where the smart quote came from
  Expose ERR_load_SSL_strings
add iOS to wordlist
support --backend as a pytest flag to limit to one backend for testing
pass posargs via tox so --backend can be used for tox envs
don't mutate _ALL_BACKENDS
better name for the variable
add conditional ERR_remove_thread_state. PyOpenSSL uses this
Specify the epub theme to fix the epub build on RTD.
Expose the nids for the various eliptical curve things. I don't understand what these mean.
Merge pull request #474 from dreid/epub-theme

Specify the epub theme to fix the epub build on RTD.
Merge pull request #475 from alex/ecdhe-nids

Expose the nids for the various eliptical curve things. I don't understa...
Expose a name needed for ECDHE -- the NIDs are always available
Merge pull request #477 from alex/expose-ecdhe-name

Expose a name needed for ECDHE -- the NIDs are always available
Document when the common crypto bindings were added
Merge pull request #478 from alex/document-cc-bindings

Document when the common crypto bindings were added
rename variable to be less confusing and terrible
Merge pull request #473 from reaperhulk/remove-thread-state

Add ERR_remove_thread_state