forgot to actually index stealth in main db_interface.
update to latest checkpoint.
remove obsolete history_result struct.
history_database::statinfo()
spend_database::statinfo()
update bucket values based on current block heights (330k)
add HACKING file with instructions for coders.
dont forget tx_db buckets in HACKING file
remove history_scan_database which needs to be rewritten anyway.
modify stealth db so everything is RHS prefix matching.
fix broken unit test.