Merge branch 'master' into urandom-engine

* master:
  PKCS #1 RSA test vector loader
  Removed pointless anchor
  Docs need virtualenv as well
  Everything about bash is the worst
  Some reST markup nonsense
  Fix for OS X
  More clearly describe the behavior of constant_time.bytes_eq
  Run the doc tests under OS X
  Made OpenSSL's derive_pbkdf2_hmac raise the right exception
  Document which backends implement which itnerfaces. Fixes #538
  pep8
  Fixed a typo in the docs
  Make the default backend be a multi-backend

Conflicts:
	tests/hazmat/backends/test_openssl.py