Added
- `lazycall` method and top-level calls implemented for implementing lazy functions that deliver chains.
- `map`, `filter` and `zip` methods added that have identical parameters to the built-ins, except they returns chains, as you might expect.
- Negative indexes have been implemented for `__getitem__`.
- New `dest` method added - returns the head and tail at the same time.
- New `expanded_len` method added to support teaching and debugging.
Changed
- Test methods slightly extended.
- Documentation expanded with the maze example.
- Backfilled CHANGELOG.md.