autoreverting remote files

[Michael Albinus]

Hi,

in autorevert.el, remote files are excluded from operation. There are
good reasons for this; mainly due to slow access.

However, there are use cases where it might be acceptable to handle
remote files, too. For example, watching a log file via
`auto-revert-tail-mode', which can be accessed as root only.

Therefore, I propose a new option `auto-revert-remote-interval'. This
shall have the same meaning as `auto-revert-interval' for local
files. The default value is nil, which means that remote files are not
reverted. And the users shall be guided, that a good value shall be
bigger than the default 5 seconds of `auto-revert-interval'.

Additionally, one would need the new defun `auto-revert-set-remote-timer'.

Opinions?

Best regards, Michael.