* Experimental MP-trie
why:
Deleting records is a infeasible with the current structure
* Added vertex ID recycling management
Todo:
Provide some unit tests
* DB layout update
why:
Main news is the separation of `Merkel` hashes into an extra table.
details:
The code fragments cover conversion between compact MPT records and
Aristo DB records as well as some rudimentary cache handling for
the `Merkel` hashes (i.e. the extra table entries.)
todo:
Add some simple unit test for the descriptor record (currently used
for vertex ID management, only.)
* Updated vertex ID recycling management
details:
added simple unit tests (mainly testing ABI)
* docu update
Jordan Hrycaj