v0.3.1

compatibility release

• drop support for Python3.8 (reached EOL), support Python3.13 instead
• switch from pipenv to venv
• use pandas >=2.2.2 and numpy >=2.0 (numpy2 and pandas2 are now compatible again)
• include separate requirements-dev
• remove travis.yml (everything runs in GitHub actions anyway)

also includes some WIP on categorisation of measures and profile comparisons