#24 Handle long integers properly for all Python versions

[Christopher Head]

In Python 2, int is a native word-sized integer up to 2³¹−1 on 32-bit platforms and 2⁶³−1 on 64-bit platforms, while long is an arbitrary precision integer. In Python 3, int is an arbitrary precision integer and long does not exist. Initialize the ordering attribute to whatever is the appropriate arbitrary precision integer type on the current Python implementation.