Tramp cleanup

Tramp cleanup

* doc/misc/tramp.texi (Remote processes): Adapt index.

* lisp/net/tramp.el (tramp-skeleton-directory-files)
(tramp-skeleton-make-symbolic-link):
* lisp/net/tramp-cache.el (with-tramp-saved-file-property)
(with-tramp-saved-file-properties)
(with-tramp-saved-connection-property)
(with-tramp-saved-connection-properties): Use `setf' but `setq' in macro.

* lisp/net/tramp-compat.el (tramp-compat-funcall): Declare debug.

* lisp/net/tramp-crypt.el (tramp-crypt-file-name-p): Exclude lock files.
(tramp-crypt-file-name-handler-alist): Use `identity' for
`abbreviate-file-name'.
(tramp-crypt-add-directory, tramp-crypt-remove-directory):
Adapt docstrings.
(tramp-crypt-cleanup-connection): New defun.  Add it to
`tramp-cleanup-connection-hook'

* lisp/net/tramp-sh.el (tramp-sh-extra-args): Extend regexp.