first stage in tidying up Real and Hyperreal.
Factor cancellation simprocs
inverse #0 = #0
simprules for division
corrected ambigous syntax definitions in Hyperreal
consts value :: boolex => (nat => bool) => bool
primrec
"value (Const b) env = b"
"value (Var x) env = env x"
"value (Neg b) env = (~ value b env)"
"value (And b c) env = (value b env & value c env)"