Get rid of req versions

install/pre-requirements.txt

-numpy==1.6.2
+numpy

install/requirements.txt

-boto==2.6.0
-coverage==3.5.3
-dogstatsd-python==0.2
-lxml==3.0.1
-mock==0.8.0
-nltk==2.0.3
-nose==1.2.1
-scipy==0.11.0
+boto
+coverage
+dogstatsd-python
+lxml=
+mock
+nltk
+nose
+scipy
 path.py
 pip
-pylint==0.26.0
-pytz==2012h
-scikit-learn==0.12.1
+pylint
+pytz
+scikit-learn