[PERSISTENCE/JSON]: okay, no more JSON backend for the moment. Simply do something more verbose and human readable.
[PERSISTENCE/BACKEND/VERBOSE]: a new 'verbose' backend (serialization only) that produce a formatted, human-readable output.
[PERISTENCE/CORE]: slower but safer and more extensible 'framework'. (even though it's 1 Gb/s that I've lost on this commit :( ).
[PERISTENCE/EADME]: updated the readme with the new 'verbose' backend and some extra informations.