ocaml: phase 6 Float module fleshed out (+6 tests, 598 total)

New Float members:
  zero / one / minus_one
  abs / neg
  add / sub / mul / div     (lift host '+.' '-.' '*.' '/.')
  max / min                 (if-based)
  equal / compare           (Float.compare returns -1 / 0 / 1)
  to_int                    (host floor)
  of_int                    (identity in dynamic runtime)
  of_string                 (delegates to _int_of_string)

Aligns Float with Int's API and lets baselines use Float.add /
Float.compare / etc without lifting the symbols themselves.

  Float.add 3.5 4.5         = 8
  Float.compare 2.5 5.0     = -1
  Float.abs -3.7            = 3.7
  Float.max 3.14 2.71       = 3.14

lib/ocaml/runtime.sx

@@ -630,6 +630,7 @@
 
    module Float = struct
      let to_string f = _string_of_float f
+     let of_string s = _int_of_string s
      let sqrt f = _float_sqrt f
      let sin f = _float_sin f
      let cos f = _float_cos f
@@ -638,6 +639,22 @@
      let ceil f = _float_ceil f
      let round f = _float_round f
      let pi = 3.141592653589793
+     let zero = 0.0
+     let one = 1.0
+     let minus_one = -1.0
+     let abs f = if f < 0.0 then 0.0 -. f else f
+     let neg f = 0.0 -. f
+     let add a b = a +. b
+     let sub a b = a -. b
+     let mul a b = a *. b
+     let div a b = a /. b
+     let max a b = if a > b then a else b
+     let min a b = if a < b then a else b
+     let equal a b = a = b
+     let compare a b =
+       if a < b then -1 else if a > b then 1 else 0
+     let to_int f = _float_floor f
+     let of_int n = n
    end ;;
 
    module Printf = struct