* Use `0.3.2`

* Replace `u64` with `NodeIndex`

* Fix Typo

* Add Pruning Logic

* Fix Some Tests

* Remove Comment

* Log Only Under STD

* Return while No Element to Append

* Optimize Pruning Algorithm

* Update Doc

* Update Doc

* Zero Copy Algorithm

* Import Missing Type

* Fix Merge Mistake

* Import Missing Item

* Make `verify` Off-Chain

* `cargo fmt`

* Avoid using NodeIndex in incorrect places.

* Simplify pruning.

* Format

Co-authored-by: Tomasz Drwięga <tomasz@parity.io>