Introduced `equal`
Introduced `internal`
Introduced `above`
Replaced `direction` by `onLeft`
Introduced `setLeft`/`setRight`
Introduced `findPosition`
Introduced `setLeft'`/`setRight'`
Replaced `calcDirection` by `diffOrd`
Bug fixed in `split`
Bug fixed in `splitLookup`
Refactored `filterWithKey`
Refactored `mapMaybeWithKey`
Refactored `mapEitherWithKey`
Refactored `partitionWithKey`
Renamed `link` to `link'`
Introduced strict `link`
Removed `cbRoot`
Refactored `updateLookupWithKey`
Refactored `delete`
Refactored `submapTypeBy`