Support python 3

Signed-off-by: Daniel Nephin <dnephin@gmail.com>

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,pre-commit
+envlist = py27,py34,pre-commit
 
 [testenv]
 usedevelop=True
@@ -7,7 +7,6 @@ passenv =
     LD_LIBRARY_PATH
 deps =
     -rrequirements.txt
-    -rrequirements-dev.txt
 commands =
     nosetests -v {posargs}
     flake8 compose tests setup.py
@@ -20,6 +19,26 @@ commands =
     pre-commit install
     pre-commit run --all-files
 
+[testenv:py26]
+deps =
+    {[testenv]deps}
+    -rrequirements-dev-py2.txt
+
+[testenv:py27]
+deps = {[testenv:py26]deps}
+
+[testenv:pypy]
+deps = {[testenv:py26]deps}
+
+[testenv:py33]
+deps =
+    {[testenv]deps}
+    -rrequirements-dev-py3.txt
+
+[testenv:py34]
+deps = {[testenv:py33]deps}
+
+
 [flake8]
 # ignore line-length for now
 ignore = E501,E203