The new function has no API compatibility with the old one, so give it
a different name to avoid confusion among caller mods, which need to
change their usage. Have a function under the old name that outputs a
helpful error message.
Merge node breaker into the generic wielder mechanism. Center the wield
inventory in all wielders' formspecs. Implement full auto-upgrade of
legacy node breakers, occurring upon use or punching of the node breaker.
Make node breaker respect on_dig hooks.
Merge implementations into a single "wielder" mechanism. Clean up the
code a bit. Fix get_player_control_bits for the dispenser (it wasn't
indicating the sneak setting). Fix drops for dispenser (dispenser_on was
dropping as itself). Show item image, as well as name, at head of form.
