109.08.00

- Cleaned up and updated the `README`.
- Changed executables to enable backtraces if `OCAMLRUNPARAM` is not set.
- Changed `Command` so that executables show build info and version info
  This happens when an executatble is called as:

    foo.exe version

  Before this change, rather than display build info, executables
  would display the not-so-helpful:

  (no option given - printing version)
- Added back `Float` rounding functions with a hardcoded direction.
- Exposed `with bin_io` and `with compare` for the =sexp_bool= type.
- Added value `Core.Never_returns.sexp_of_t`.
- Added values `Or_error.tag{,_arg}`
  These are analogous to `Error` functions of the same name.
- Added functor `Sexpable.Of_sexpable`
  This is for serializing values of one type as though it were some
  other isomorphic type.
- Added module `Backtrace.Exn`
  This exposes OCaml stdlib's `Printexc` functions for backtraces.
- Added module `Flags`
  This implements Unix-style sets of flags that are represented as an
  `int` with various bits set, one bit for each flag, e.g.,
  `Linux_ext.Epoll.Flag`.
- Added module `Uuid`
  This module implements universally unique identifiers based on version
  3 of the UUID specification.  It used to be in `Core_extended=`
- Added module `Type_equal`, which defines the "equality" GADT.