Reorganized the outline to workaround a bug in Leo, also added .gitignore for .leo_shadow/.
Bug fixes to built-in functions.

- make N7::...::cp() only transfer a file if its local and remote md5
  sums differ.

- fix a bug in N7::remote:files::file() that always makes mode changes.

- change the behaviour of the -m cmdline option such that a - in it will
  cause n7 to read from stdin the hosts, and the old behaviour of
  reading hosts from stdin if -m is missing is removed.

- change state is still a mess.