* lisp/textmodes/reftex-toc.el: Improve multi-frame behavior

* lisp/textmodes/reftex-toc.el: Improve multi-frame behavior

* lisp/textmodes/reftex-toc.el (reftex-toc-revert): Avoid displaying
the buffer in yet another frame.
(reftex-toc-visit-location): Make sure toc-window has focus at the end
when `final' is nil.
(reftex--rebuilding-toc): Defvar to avoid `boundp' and
silence warnings.  Use `--' to clarify that it's internal.
(reftex-toc-next, reftex-toc-previous, reftex-toc-demote)
(reftex-toc-promote): Clarify unused argument.
(reftex--pro-or-de, reftex--start-line, reftex--mark-line):
Add `reftex--' prefix.  Fix all users.
(reftex-toc-promote-prepare): Use _ for dummy variable.
(reftex-toc-restore-region): Rename `m