Revert "delete obsolete script"

This reverts commit f8267c1c1abe05fcfbc33448efb599c7e2467f69.

duh, this script is called by myproc.
fully cleanup output directories, without clobbering files we need
build calls myproc
restore_state_from_file(): initialize the "owns" field of effects converted from older projects
mute_level(), fade_out_level(), fade(), fadein(), fadeout() are now Effect methods.

Change parameter order: _modify_effect($parameter, $value, $sign)
so that $sign can be omitted when simply setting a parameter value

Fix auto mute/unmute on Master track during changes that may cause pop