Castlevania-style whip plus sub-weapon

IPS patch for the original Vampire Killer ROM (SHA-1 b58e77f819dfbde72845801cff4b4e0a2f20ef5f).

The leather or chain whip stays equipped together with one of knife, axe, or cross.

• SPACE, or joystick fire without stick-up, whips.
• SHIFT, or stick-up plus fire, throws the sub-weapon when one is equipped.
• The weapon box shows the sub-weapon, otherwise the chain, otherwise an empty frame.
• A missed axe or cross clears only the sub-weapon. Death clears both.