Added
- `show_courses` got a `--filter` option to facilitate finding the right course.
- `canvascli` now has a `--version` flag.
- Shell completion.
Changed
- The package was refactored to modularize functionality into subcommands, each with its own options.
- `dataclassy` is being used instead of `dataclasses` from `stdlib` in order to handle class inheritance with default values.