TST: for travis: pip install requirements file.

Author: Ben Cipollini

.travis.yml

@@ -30,10 +30,9 @@ install:
 - if [ ${TRAVIS_PYTHON_VERSION:0:1} == "2" ]; then pip install ordereddict; fi
 - conda install --yes numpy scipy nose networkx dateutil
 - if [ ${TRAVIS_PYTHON_VERSION:0:1} == "2" ]; then conda install --yes traits; else pip install traits; fi
-- pip install nibabel
 - pip install python-coveralls
 - pip install nose-cov
-- pip install future
+- pip install -r requirements.txt  # finish remaining requirements
 - pip install https://github.com/RDFLib/rdflib/archive/master.zip
 - pip install https://github.com/trungdong/prov/archive/rdf.zip
 - python setup.py install