move abc, inline introspect method, use six for abcs

* abc moved to cryptography.primitive.interfaces
* six added to dependencies
* six used to have py2x/py3x compatible abc
* nonce abc removed for now

1 files changed, 1 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 4d17ebe8..02d521b1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,6 +5,7 @@ envlist = py26,py27,pypy,py32,py33,docs,pep8
 deps =
     pytest-cov
     pretend
+    six
 commands = py.test --cov=cryptography/ --cov=tests/
 
 [testenv:docs]