Add tox.ini to run tests under Python 2.7 and 3.4

tox.ini

@@ -0,0 +1,27 @@
+[tox]
+envlist = py27,py34
+
+[testenv]
+deps =
+    mock
+    pep8
+    pyflakes
+
+commands =
+    ./run_tests.py -i
+
+
+[testenv:py34]
+# Hacky Python3 mangling: the test code has to be converted using 2to3
+# before testing
+
+changedir={envdir}
+
+commands=
+  rm -rf test/
+  cp -r {toxinidir}/test/ test/
+  2to3 -w --no-diffs -n test/
+  rm -rf run_tests.py
+  cp {toxinidir}/run_tests.py .
+  2to3 -w --no-diffs -n run_tests.py
+  ./run_tests.py -i