* Fix missing Merkle key removal in `merge()`
* Accept optional root hash argument in `hashify()`
why:
For importing a full database, there will be no proof data except the
root key. So this can be used to check and set the root key in the
database descriptor.
also:
Associate vertex ID to `hashify()` error return code
* Added Aristo Trie traversal function
why:
* step along leaf vertices in sorted order
* tree/trie consistency checks when debugging
* Enabled storage slots test data for Aristo DB
Jordan Hrycaj