Cleanup ignat99 feat

New PR from https://github.com/Ignat99/OpenBazaar/pull/1 directly into OpenBazaar:develop.
Per [PEP8](http://legacy.python.org/dev/peps/pep-0008/#imports), imports should be grouped in 3 sections separated with blank lines. It is also conventional to use alphabetic ordering within each section. I know we haven't been following any of these closely. Can you help us?