Adds tox configuration.

Adds tox.ini to support running the tests on multiple versions. Adds
requirements.txt to support dependency installtion via pip.

.gitignore

@@ -9,3 +9,6 @@ dist
 /man
 nosetests.xml
 .coverage
+.tox
+.idea
+.cache

requirements.txt

@@ -0,0 +1 @@
+-e .

tox.ini

@@ -0,0 +1,20 @@
+# Tox (http://tox.testrun.org/) is a tool for running tests
+# in multiple virtualenvs. This configuration file will run the
+# test suite on all supported python versions. To use it, "pip install tox"
+# and then run "tox" from this directory.
+
+[tox]
+envlist = py26, py27
+
+[testenv]
+deps=pytest
+# This creates the virtual envs with --site-packages so already packages
+# that are already installed will be reused. This is especially useful on
+# Windows. Since we use lxml instead of compiling it locally (which in turn
+# requires a Compiler and the build dependencies), you can download
+# it from http://www.lfd.uci.edu/~gohlke/pythonlibs/#lxml and install it via
+# $PYTHONDIR\Scripts\pip.exe install *.whl
+#sitepackages=True
+commands =
+    pip install -r requirements.txt
+    py.test