Switch to PyCrypto dependency.
Ignore more cruft.
Use README.rst vs README.md.

- Easier to share reStructuredText README with Python packages.
- Add symlink from .txt to .rst to deal with github nonsense.
Ignore .cfg files.
Partial work from ages ago.

- Some partial config and other updates were done long long ago but
  never checked in.
- This code is broken in different ways than before.
- Updates coming to fix it all.
Start of update to newer PaySwarm and JSON-LD.

- Update JSON-LD usage:
  - Use common payswarm context.
  - Use aliased keywords (id, type, etc).
- Move constants to their own file.
- Add packaging info.
  - setup.py
  - MANIFEST.in
  - requirements.txt
  - test-requirements.txt
- Add signature test.
- Add test support to Makefile
  - basic
  - coverage
- Update README.
- Use PyCrypto instead of M2Crypto
- Remove OAuth2 usage.
- Add urllib3 support if available to support SNI.
- Update signature signing support.
- Add signature verifing support.
- Update hash output format.