use all the cores on the box

- python setup.py install

script:

- nosetests --with-flaky -a '!slow' --with-timer --with-coverage --cover-package=deepchem --processes=-1 -v deepchem --nologcapture

--processes=NUM¶

- find ./deepchem | grep .py$ |xargs python -m doctest -v

- bash devtools/travis-ci/test_format_code.sh

after_success: