add errors option to cast_bytes/unicode
py3/unicode fixes for auth

tests should be passing on Python 3
test_auth tweaks

- remove unnecessary hasattr
- set log-level to debug during tests
run nose in subprocess

in setup.py tests

fixes log capture for some reason
Python 2.6 is stupid
use IOLoop.instance in auth

not current
py3 pass on security examples
use logging instead of print
default to Context instance in auth
mixed_camelCase is confusing on attrs
single ioloop-ironhouse example
mention zmq.auth in changelog
DelayedCallback is deprecated
add socket method to base test case
cleanup pass on test auth
Merge pull request #453 from minrk/py3auth

py3/unicode fixes for auth