EUDC: Enable lexical binding and do some cleanups

EUDC: Enable lexical binding and do some cleanups

* lisp/net/eudc.el: Enable lexical binding.
(cl-lib): Always require cl-lib, not only when byte compiling.
(eudc-mode-map): Set parent keymap within let form.
(eudc-update-local-variables): Use #' read syntax for function
argument to map function.
(eudc-select): Likewise.
(eudc-format-attribute-name-for-display): Likewise
(eudc-filter-duplicate-attributes): Likewise.
(eudc-format-query): Likewise.
(eudc-expand-inline): Likewise.
(eudc-query-form): Likewise.
(eudc-print-attribute-value): Use mapc instead of mapcar.
(eudc-filter-partial-records): Use cl-every.
(eudc-distribute-field-on-records): Use delete-dups to
simplify function.
(eudc-expand-inline): Replace while with dolist and let form.
(eudc-query-form): Set inhibit-read-only after switching
buffers.  Remove useless and call.
(eudc-load-eudc): Add a FIXME comment.