* list/progmodes/idl*.el: Use lexical-binding

* list/progmodes/idl*.el: Use lexical-binding

* lisp/progmodes/idlw-complete-structtag.el: Use lexical-binding.

* lisp/progmodes/idlw-help.el: Use lexical-binding.
Delete redundant `:group` arguments.
(idlwave-query-class, idlwave-force-class-query, idlw-help-name)
(idlw-help-kwd, idlw-help-link): Declare vars.
(idlwave-highlight-linked-completions): Remove unused var `class`.
(idlwave-help-find-in-doc-header): Remove unused var `header-re`.

* lisp/progmodes/idlw-shell.el (idlwave-shell-input-mode-magic):
Remove XEmacs-only code.
(idlwave-shell-filter, idlwave-shell-scan-for-state):
Use `functionp` since a function can also satisfy `listp`.
(idlwave-shell--mouse-examine): Rename from `idlwave-shell-mouse-examine`.
Make it a function, and simplify for Emacs≥22.  Simplify calling convention
since all callers always immediately `funcall`d the result.
Update all callers.
(idlwave-default-mouse-track-event-is-with-button): Use `always`.
(idlwave-shell-filter-bp): Simplify a tiny bit.

* lisp/progmodes/idlw-toolbar.el: Use lexical-binding.
(idlwave-toolbar-add, idlwave-toolbar-remove)
(idlwave-toolbar-add-everywhere, idlwave-toolbar-remove-everywhere)
(idlwave-toolbar-toggle): Remove XEmacs-only code.

* lisp/progmodes/idlwave.el: Use lexical-binding.
(idlwave--dlet): New macro.
(<toplevel>): Use it.
(idlwave-keyword-abbrev): Turn it into a function.
(idlwave-code-abbrev): Delete macro.
(idlwave-mode-abbrev-table): Use `:enable-function` instead.
(idlwave-with-special-syntax): Delete macro; use `with-syntax-table`
instead in all callers.
(idlwave-action-and-binding): Use `alist-get` and replace `(lambda...)
with a proper closure.  Change all callers to prefer passing a function
in the `cmd` argument.
(idlwave-fill-function): Delete constant var.
Replace its uses with its value (the symbol `auto-fill-function`).
(idlwave-mode): Set `normal-auto-fill-function` instead of the
cumbersome use of `idlwave-fill-function`.  Tighten a regexp.
Don't set `imenu-create-index-function` to the value it should already have.
(idlwave-auto-fill-mode): Make it an obsolete alias for `auto-fill-mode`.
(idlwave-modify-abbrev): Rename from `idlwave-check-abbrev`.
Don't check `idlwave-quoted` since `:enable-function` did it for us already.
(idlwave--command-function): Rename from `idlwave-command-hook`
and make it hold a function rather than an expression.
(idlwave-command-hook, idlwave-modify-abbrev): Adjust accordingly.
(idlwave-show-begin-check): Don't check `idlwave-quoted` since
`:enable-function` did it for us already.
(idlwave-do-action): Use `functionp` since a function can also satisfy `listp`
(idlwave-new-sintern-type): Make it a macro, so we don't need to
`declare-function` for the functions it defines.
(idlwave--class-selector, idlwave--type-selector)
(idlwave--method-selector, idlwave--super-classes): Rename those vars
by adding the `idlwave--` prefix.  Adjust all uses.
(idlwave-complete-functions): Rename from `idlwave-complete-special`.
(idlwave-call-special): Declare obsolete.  Change all callers to use
`run-hook-with-args-until-success` instead.
(idlwave-complete-filename): Use `dlet`.
(idlwave-rinfo-assq-any-class): Remove unused var `class`.
(idlwave-determine-class-functions): Rename from
`idlwave-determine-class-special`; fix docstring since the functions
are called with only one argument.
(idlwave--complete-after-success-function): Rename from
`idlwave-complete-after-success-form` and make it hold a function.
Adjust all users.
(idlwave--complete-after-success-force-function): Rename from
`idlwave-complete-after-success-form-force` and make it hold a function.
Adjust all users.
(idlwave-attach-classes): Remove always-t variable `do-dots`.
(idlwave-local-value): Use `local-variable-p` and `buffer-local-value`
to avoid `with-current-buffer`.
(idlwave-default-choose-completion): Comment out (unused and calls
a function that doesn't exist).
(idlwave-shell-filter-sysvars): Remove unused vars `type`, `name`, and `class`
(idlwave-fix-module-if-obj_new): Remove unused var `name`.
(idlwave-fix-keywords): Bind `idlwave--super-classes` via `let` than
via the function's argument.
(idlwave-twin-class, idlwave-twin-name): Move before first use.
(idlwave-study-twins): Remove stealth/redundant `type` variable.
(idlwave-routine-entry-compare-twins): Remove unused var `type`.
(idlwave-path-alist-add-flag): Avoid `add-to-list` on a local var.
(idlwave-list-abbrevs): Simplify a tiny bit.