Add some missing test coverage for handling values of type `long` and fix the implementation to accept either `int` or `long` on Python 2 (more closely matching the API implemented by the old C code).
tests and fixes for other int/long cases
Merge pull request #28 from pyca/other-int-fixes

Add some missing test coverage for handling values of type `long` and make them pass by loosening the explicit type checks in various APIs.