Update README.md
Bug fix: `erfi:$` with last `$*`.

`erfi:$` generated lambda with rest parameter as in Scheme fashon;
`(lambda args ...)` is not available in Emacs Lisp.  It is changed to
generate `(lambda (&rest args) ...)`.
Use `lexical-binding` t.
`flet` is in `cl.el`
Code cleanup.
Re-implement `cut` and `cute`.

- Do not trust the order of evaluation of `mapcar`.  Current
  implementation is as we expected, but it is not documented.
- `cut` and `cute` share code-walker.
- As `erfi:$` allows functions without quotes, `cut` and `cute` do.
  Note that there is a restriction for use of this and rest parameter
  <...> together because Emacs Lisp is Lisp-2.  In this case one have to
  use quote.  Also there are ambiguities for variables and functions.
  See `erfi-test:cut:allows-no-quote`.  `erfi:$` contains the same
  problem.
Add comment: `erfi:$`

The same restriction with `cut`.
See commit a4c6fa2fe55006041f87ac8fbefd7a8b2d6c3687.