Iftttie

- Feat: user authentication
- Chore: add `dev` install extra
- Chore: enable `pytest` in Travis

- Fix: `id_` for `File` and `Clock`
- Opt: set `PYTHONOPTIMIZE=2` for the Python interpreter
- New: 10 set up unit testing and get rid of `aiosqlite` for now
- New: 9 database schema migrations

- New: charts in the detail views
- Fix: passing options via environment variables
- Change: always start on port `8443`
- Opt: use [`aiohttp-sse-client`](https://pypi.org/project/aiohttp-sse-client/)
- Change: 2 4 6 Change database schema, rename `ValueKind` and add titles
- Chore: 4 refine `Unit` class
- Chore: 5 6 denormalise database and add update IDs

- Opt: improve `Dockerfile` and `Makefile`
- Opt: improve `Nest` and `Buienradar`
- Chore: move text constants to templates
- New: introduce new value kinds
- New: add SSL support
- New: detail view page
- Change: use `pickle` instead of JSON to store values in the database

- New: initial release