lib/sh/archives.sh: zip(), unzip(): added missing echo_func

lib/sh/util.sh: command(): use just one control var $cmd_log_fd instead of three flags (limit_log_fd, limit_stdout, stderr_is_errors) that indicated various common fd configurations. this is much clearer (you state which fd the common uses as its logging fd), more configurable (the logging fd can be any fd, not just 1 or 2), and more automatic (redirecting fd 2 to err_fd happens automatically if it isn't used for logging).

bugfix: lib/sh/local.sh: psql(): need to use limit_stdout=1 instead of stderr_is_errors=1 because logging info is output to stdout, not stderr, in spite of the >&2 redirection, since the >&2 is applied after command()'s logging redirects. note that the >&2 can now be removed, because it will be performed by command().

lib/sh/util.sh: added $log_fd and use it instead of 2 where the log_fd is intended

lib/sh/util.sh: moved stdout2log_fd() to command verbose output subsection of verbose output since it is primarily intended for use with external commands

lib/sh/util.sh: renamed limit_stderr to limit_log_fd, stdout2stderr to stdout2log_fd to clarify their purpose. log_fd is currently assumed to be 2.

lib/sh/util.sh: added disable_logging() and use it instead of `exec 2>/dev/null`

lib/sh/util.sh: added $err_fd global var and use it instead of the 22 magic value. it starts out at 2 until fd 22 has been set up, so commands that required 22 will now work before set_global_fds() is called.

lib/sh/util.sh: shadow_fd(): don't require it to be run with log++ and instead let callers apply log++ if needed. in set_global_fds(), log++ can just be applied once for all the shadow_fd() calls.

lib/sh/util.sh: shadow_fd(): instead of applying minor=1 (i.e. an additional log++) to echo_func and then log++ again separately to set_fd, just apply it to the entire function