Add music_ops.sh, music_convert_m3u.sh: helpers for music management.
trim_all.sh, trim_unused.sh: require positive acknowledge (CONFIRM=1).

Default (ignorant) launch must be safe.
pack.sh: change signals, QUIT is wrong (requests core dump).
mount-iso: pass '-y' to fsck.
systemd_plot.sh: replace with boot_analyze.sh.
dropbox_find_conflicts.sh: fix directory creation, logging and search pattern.
lan_vnc.sh: Tight is actually better, also use AutoSelect.
Add icsy: wrapper for icsy with mpv and absolute time.
Add arch_mirror_sync.sh: a modified script for syncing with Arch repos.