- Move Functional to Details, to get more time to think about it
- Move Either to Details, to get more time to think about it
- Prettify some examples
- Better introduction of the "Data types" documentation module
- Split type class instances into separate files
- Instances provided automatically by a type class are actually MCDs
- Test each instance in a single file, not one file per method
- Refactor the operator system to fix the ADL-related bug.