Stable v0.12.1

Release v0.12.1

Add -i flag for case-insensitive matching

Stable v0.12.0

Release v0.12.0

Prepare for new colout version

Because there is a weird v0.11 tag, we pick the next version v0.12.0,
instead of the "real" next version aka v0.7.0

This project is considered to use Semantic Versioning (https://semver.org/)
(https://semver.org/spec/v2.0.0.html as of now)

• Python versioning updates: Unify that package is offered for >=Python3.5
• A lot of metadata / internal files updated
• Update README.md