lib/sh/util.sh: merged limit_stderr_cmd/limit_stdout_cmd into command(), using flag vars to control what limiting actions it needs to perform. in command invocations, this involves setting the appropriate flag vars instead of using a limit_std*_cmd alias.

lib/sh/util.sh: added run_cmd

lib/sh/util.sh: limit_stderr(): moved before command echoing because it does not depend on it and is a separate feature

lib/sh/util.sh: run_args_cmd(): use $top_script instead of `"$(canon_rel_path "$0")"`

lib/sh/util.sh: $top_script: run canon_rel_path on $0

lib/sh/util.sh: use `minor=1 echo_func` instead of echo_minor_func because the syntax is simple enough that you don't need a separate alias for it

lib/sh/util.sh: echo_func: support using minor=1 to increase the log_level that the function call is echoed at. use this in echo_minor_func.

lib/sh/util.sh: echo_*func aliases: use simpler && syntax (with `|| true` to prevent errexit if the condition is false) instead of an if statement. this also allows prefixing the alias with var definitions.

lib/sh/util.sh: echo_*func aliases: use simpler && syntax (with `|| true` to prevent errexit if the condition is false) instead of an if statement. this also allows prefixing the alias with var definitions.

lib/sh/util.sh: echo_func: only indent if the function call was displayed. this avoids confusing extra whitespace when a function call causes an indent but the function call itself isn't printed.