Arghelper

Added
- Migrated from Travis-CI's legacy to container-based
infrastructure.
- Added pandoc to Travis-CI's addons

Added
- Updated requirements.txt

Fixed
- `parse_config_input_output()` had an error causing it to fail.

Fixed
- Fixed all links due to moving Github repo:
- **Old:** https://github.com/matthewrankin/arghelper
- **New:** https://github.com/questrail/arghelper

Added
- Automate PyPI deployment
- Change badges to use shields.io
- Move CHANGES.md to CHANGELOG.md

Added
- Initial release to Github. Not released to PyPI.

[arghelper]: https://github.com/questrail/arghelper