Reduce the surface of the primitive hash interface.  Add more interfaces, drop direct hashlib compatibility.
Ignore abstractproperty.
Fix python3 compatibility and pep8
blowfish support + test vectors

Vectors sourced from https://www.schneier.com/code/vectors.txt but
reformatted to comply with our NIST loader
add blowfish cipher key_size tests
add bf docs
Merge branch 'master' into primitive-hashes
Update documentation
Fix python3 compat for the hash_test.
move blowfish docs to new weak ciphers section, linkify aes
Enforce that Hash takes a HashAlgorithm instance.
Inline _copy_ctx
Disable coverage on pypy temporarily.
Merge pull request #201 from reaperhulk/bf-support

Blowfish Support
CAST5 support + ECB vectors
add CAST5 docs
add skipif checks for blowfish
Merge pull request #208 from reaperhulk/skip-check-blowfish

Add skipif checks for blowfish
Merge pull request #207 from dreid/temp-disable-coverage-on-pypy

Disable coverage on pypy temporarily.
disable support for CAST5 modes excepting ECB