fix hash for +inf.0, -inf.0, +nan.0; cannot use frexp; also hash 0.0 and -0.0 differently
fix hash for +inf.0, -inf.0, +nan.0; cannot use frexp; also hash 0.0 and -0.0 differently

svn: r2177

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket