OpenBazaar/OpenBazaar — pull request #595 by Renelvon (2014-09-17 00:27:42+00:00)
Title: Drop node/arithmetic.py

### Changelog:
* Unit test a small part of `pybitcointools` API.
* Use `pybitcointools.main` instead of `node/arithmetic.py`.
* Drop `node/arithmetic.py` and `test/test_arithmetic.py`. See #590.