[Trans] Verifying inclusion proof

[Ondrej Mikle <[e-mail]>]

Pardon me if I am asking something obvious, but I'm missing one piece of
information for inclusion proof verification - the "placement" of each
node returned from "get-proof-by-hash" method in audit_path list
(whether it's left subtree or right subtree).

Since the hashing of concatenation of strings is not commutative, the
auditor needs to put the two partial tree hashes in correct order to get
to the correct root hash.

I'd guess the placement of the missing nodes from audit_path could be
derived from leaf_index and tree_size, but can't see a straightforward
way to do it. The reference client does not implement this verification
either.

Ondrej