A lot of code standardising for the way machines handle trying to take money from a user.
All machines can now be set to connect to the accounts database in initialize().
reconnect_database(), connect_account(), and scan_card() have all been moved to the machine level.
Merch computer now reads your equipped ID, not your mind account. Fixes#2854.
All machines getting your ID using get_id_card() now check all your slots, with hands being prioritised over the ID slot.
Removed a pointless human-only proc that was causing befuddlement.