lib/sh/util.sh: moved functions echoing section before other types of echoing so they can use echo_func()

lib/sh/util.sh: $verbosity: decreased default value to 1 so that normally, only external commands are echoed. this avoids cluttering up the output with the function call tree, which is really only needed for debugging. it also mirrors make's default verbosity (i.e. print external commands and subdir recursions, but not make's internal actions).

*{.sh,run}: put doc comment on next line when possible, so that the function name always comes before it

lib/sh/util.sh: put usage message at end of line when possible, so that the function name always comes before it

bugfix: lib/sh/util.sh: $top_script: need to realpath this before doing any cd so this points to the right place. set and use $top_script_abs for this purpose.

lib/runscripts/util.run: added setting of $top_file, $top_filename to set_paths()

lib/runscripts/util.run: set $top_file, $top_filename in a function (set_paths__util_run())

lib/sh/util.sh: cd(): re-run set_paths() to update $top_script, $top_dir for the new current dir

lib/sh/util.sh: added set_paths(), which sets $top_script, $top_dir

lib/sh/util.sh: moved $top_script, $top_dir before internal commands echoing so they can be reset in cd()