critical(hangs):Rational#** when passed Bignum returns positive Infinity when self is > 1
critical(hangs):Rational#** when passed Bignum returns 0.0 when self is > 1 and the exponent is negative
critical(hangs):Rational#** when passed Bignum returns positive Infinity when self < -1
critical(hangs):Rational#** when passed Bignum returns 0.0 when self is < -1 and the exponent is negative
fails:Rational#** raises ZeroDivisionError for Rational(0, 1) passed a negative Rational
