Check minimum NumPy versions to build against in ``.travis.yml`` file. Build against the earliest NumPy that Pillow is compatible with; see `forward, backward numpy compatibility <http://stackoverflow.com/questions/17709641/valueerror-numpy-dtype-has-the-wrong-size-try-recompiling/18369312#18369312>`_
Wheels are uploaded to a `rackspace container <http://a365fff413fe338398b6-1c8a9b3114517dc5fe17b7c3f8c63a43.r19.cf2.rackcdn.com/>`_. Credentials for this container are encrypted to this specific repo in the ``.travis.yml`` file, so the upload won't work from another repository.
