------------------
- Bow to flake8
- py-seccure did not pad a signature with zeroes as seccure expected.
This caused some signatures generated by py-seccure not being accepted
by seccure. This has been fixed. Old unpadded signatures are still
accepted by py-seccure to keep backwards compatibility.
See 16 (Thanks-to: Tanner Collin)
- Add support for Python 3.7
- Drop support for Python 2.6 & Python 3.3