add docopt to tox

tox.ini

@@ -3,6 +3,8 @@ envlist = py26, py27, py32, py33
 [testenv]
 deps =
     https://bitbucket.org/hpk42/pytest/get/c4f58165e0d4.zip
+# docopt for sith doctests
+    docopt
 commands =
     py.test []
 [testenv:py26]
@@ -17,7 +19,5 @@ commands =
     coverage run --source jedi -m py.test
     coverage report
 [testenv:sith]
-deps =
-    argparse
 commands =
     {envpython} sith.py --record {envtmpdir}/record.json random {posargs:jedi}