Advarchs

Fixes:
- tests using 7zip utility (including RAR files) on Windows, Ubuntu 18.04+, Alpine

New:
- Implemented CI/CD using travis 🤓
- Alpine Dockerfile 🐳

Docs:
- Badges in README 😄
- Apache 2.0 License
- Contributing guide

Bugs:
- Will not unrar on CentOS 7,6 or Ubuntu <= 16.04 using 7zip