migrate mmfile from libbitcoin to libbitcoin-blockchain
migrate history_database to just being a list of rows for outputs AND spends.
remove cruft from spend_db tool
rename history_database::add_row() to add_output()
history_row_id was renamed to point_ident
change history_scan_database to match fetch_history() semantics.
history_row_id renamed to point_ident: update tools and tests
update benchmarks to fix compile errors.
update database bucket values.
update fullnode example.