destroy armor from spork

Magic resistance will reduce the amount by which your stuff is fiddled
but it won't actually stop things from being damaged.

Everything, including formerly indestructible DSM etc may be destroyed.

Includes:
https://github.com/Bulwersator/CopyOfSporkHack/commit/65746a16b1876640d181276828aae7421cbac5e3
https://github.com/Bulwersator/CopyOfSporkHack/commit/c747690e1b7cd22e47d6bddebd3ce5853b009068
https://github.com/Bulwersator/CopyOfSporkHack/commit/14de49be7f5c249d9c3e140317df28ba4ef43482
https://github.com/Bulwersator/CopyOfSporkHack/commit/6a1be125cce4ce8f42da4c70783a07b7c8006f6d

Additionaly fixes problems: formerly undamagable things like DSM may be
destroyed so now it is possible to wish for "protected dragon scale
mail", fooproof status is displayed. Items with secondary erosion may be
destroyed, code duplication removed.

Additionaly: additional damage to object to fully damaged object carried
by player will destroy it, it is not limited to destroy armor monster
spell.