SERA for file I/O

  Whenever you find a file (by `C-x C-f') whose name ends in
`.sera',
Mule assumes that the file is written in SERA, and automatically
converts the contents into Fidel.

  Likewise, if you save a buffer to a file with the `.sera'
extension,
the contents will be converted into SERA before actually written.

  Note that the old two hooks for SERA I/O, i.e.,
`fidel-to-sera-for-disksave' and `sera-to-fidel-for-disksave', have
been
removed.