Answer the index of the high order bit of the receiver, or zero if the
receiver is zero. Raise an error if the receiver is negative, since
negative integers are defined to have an infinite number of leading 1's
in 2's-complement arithmetic. Use >>highBitOfMagnitude if you want to
get the highest bit of the magnitude.
Answer an instance of the receiver which in some sense is initialized. In the case of Morphs, this will yield an instance that can be attached to the Hand after having received the same kind of basic initialization that would be obtained from an instance chosen from the 'new morph' menu. Return nil if the receiver is reluctant for some reason to return such a thing