These two options are pure setuptools functionality and problematic:
https://pip.pypa.io/en/stable/user_guide/?highlight=setup_requires#installation-bundles

Also fixes other memory leads. Previously, load_index_seq_as_long did
not correctly DECREF the new reference created by PySequence_Fast.

fixes #10

Python2's weird comparison semantics are inconsistent with what
we expect when `NotImplemented` is returned.

If the arrays do not have the same shape then we return NotImplemented.

A new method `object_size` is added to the Array template class, which
calculates the total size of the Python object in bytes.  The function
`size_of` then wraps this method and provides the necessary interface
for a Python method object.

This makes it fail for Python 3 also on 64 bit platforms.