Add mount options to data getmountlist collects.
Switch mtab_list to doubly linked so we can traverse in either order. Convert umount and df. Add dlist_terminate() to break lists for traversal in either direction.
Make "losetup /dev/loop0 filename" work.

Sigh. Implement the complex cases and you screw up the simple cases you already tested...
First stab at mount, very incomplete.
strings - print the strings in the file.
makedevs - making devices/nodes in a range. Supports reading the tabled entry from file.
killall5 - kill all the processes not in its session.