Fixes #1024 -- a utility function for checking an implementor against an ABC
whoops, forgotten file
Added header
py3k fix
Fix for abstractproperty, and make things nicer
fix up the line coverage
Merge branch 'master' into verify-interfaces

Conflicts:
	cryptography/utils.py
Statically verify interface implementations, and fix all the resulting bugs
fixed some naming in the tests
Merge branch 'master' into verify-interfaces

Conflicts:
	tests/hazmat/primitives/test_hmac.py
Merge branch 'master' into verify-interfaces

Conflicts:
	cryptography/hazmat/primitives/hmac.py
Merge branch 'master' into verify-interfaces
Merge branch 'master' into verify-interfaces
make things happy
make this test happy
satisfy the cmac tests as well
Merge branch 'master' into verify-interfaces

Conflicts:
	tests/hazmat/backends/test_commoncrypto.py
	tests/hazmat/backends/test_openssl.py
	tests/hazmat/primitives/test_block.py
	tests/hazmat/primitives/test_hashes.py
	tests/hazmat/primitives/test_hmac.py
	tests/hazmat/primitives/test_pbkdf2hmac.py
many verify, for now
Refactor .travis/install.sh.
Fix missing ;;