Changes

Summary

1. discontinued unclear timeout (stemming from jEdit JSch setup, see 14782d58a503), to make it work with native Windows ssh.exe;
2. proper time values in seconds;
3. clarified run_sftp: avoid platform_path via careful use of tmp_dir, to support both Windows and Cygwin ssh; discontinued run_scp: use run_sftp instead;
4. more robust, notably for macOS (see also ff92d6edff2c);
5. back to plain /tmp (despite 1df53737c59b): relevant for ssh on macOS, to avoid error "unix_listener: path too long for Unix domain socket";
6. tuned names;
7. proper order of platforms, to make it work uniformly on all plaform families;