fix tox deps; correct test instructin in README

[ci skip]

README.rst

@@ -48,6 +48,7 @@ To run for specific version, setup a ``virtual environment``::
 
     virtualenv -p python3 py3
     source py3/bin/active
+    pip install -r requirements.txt
     make test
 
 To run for ``python 2.7`` and ``3.4`` assuming you have them installed::

tox.ini

@@ -4,11 +4,6 @@ envlist = py27, py34
 [testenv]
 setenv =
     PYTHONHASHSEED = 0
-deps =
+deps = -rrequirements.txt
-    nose
-    coverage
-    mock
-    vcrpy
-    pyyaml
 commands =
 	nosetests --verbosity 1 --with-coverage --cover-package=steam