Use tox -e pypy on Travis CI for PyPy 2.7 and 3.5
Use tox -e pypy on Travis CI for PyPy 2.7 and 3.5

pypa/pip,rouge8/pip,pradyunsg/pip,sbidoul/pip,pfmoore/pip,rouge8/pip,rouge8/pip,pradyunsg/pip,xavfernandez/pip,pfmoore/pip,sbidoul/pip,pypa/pip,xavfernandez/pip,xavfernandez/pip