add brewed openssl to travis osx
move script to separate file for readability
let's see what version of openssl is already installed on these slaves
remove unneeded openssl bottle
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
remove comment that's no longer needed
Merge pull request #465 from reaperhulk/comment-fix

Remove comment that's no longer needed
Verify the tag len for GCM
Merge pull request #467 from alex/validate-tag-len

Verify the tag len for GCM (docs)
check if openssl is installed via homebrew on osx. install if not
Merge pull request #448 from reaperhulk/travis-add-brew-osx

Add Homebrew OpenSSL to Travis OS X Matrix
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
Start binding some stuff for ECDHE in pyOpenSSL.