(tramp-default-method): New default method "sm"

(tramp-default-method): New default method "sm"
which I guess to be good for most people.
(tramp-default-method-alist): Use "ftp" method (ie, forwarding to
Ange-FTP) for some user/host combinations.
(tramp-file-name-structure, tramp-file-name-regexp)
(tramp-make-tramp-file-format)
(tramp-make-tramp-file-user-nil-format)
(tramp-multi-file-name-structure)
(tramp-multi-file-name-hop-structure)
(tramp-make-multi-tramp-file-format): New default value which
unifies the filename syntax between Tramp and Ange-FTP.  The new
syntax is "/method:user@host:path".  Note the colon after the
method.
(tramp-handle-file-name-directory): Don't return "/" when
completing a remote root directory (where the filename looks like
"/method:user@host:/").
(tramp-handle-ange-ftp): Deleted.
(tramp-disable-ange-ftp): New function, called at toplevel,
deletes Ange-FTP from file-name-handler-alist.