Sdfascii

- Updated dependencies.
- Added Python 3.6 to travis.yml.

Added
- Invoke `inv test` task now checks for test coverage.

Changed
- Migrated from Travis legacy to container-based infrastructure.
- Updated numpy from 1.8.1 to 1.9.2.
- Updated other pip requirements.

Enhancements
- Add license badge
- Renamed AUTHORS.txt to AUTHORS.md
- Updated README.md

Enhancements
- Changed to shields.io for badge service

Bugs
- Fixed unit tests in Python 2.6 [6][]

Enhancements
- Made Python 3.3/3.4 compatible [5][]