fix tox.ini file

Tox now uses the development client lib in the local repo instead
if using setup.py to install it into every environment. Also
added deps that points to requiremnts.txt so tox installs the needed
dependencies

tox.ini

@@ -1,6 +1,9 @@
 [tox]
 envlist = py26, py27, py32, py33
+skipsdist=True
 [testenv]
+usedevelop=True
 commands =
-    {envpython} setup.py install
     {envpython} tests/test.py
+
+deps = -r{toxinidir}/requirements.txt