resize_ffs(8) TODO list

* Determine why shrinking a v1 file system gets the free block/frag info
  wrong, requiring a fsck.
* Add support for swapped byte order
* Fix support for disk blocks of size other than 512 bytes
* Add support for plain files (primarily to ease testing)
* Extend to support UFS2.  Probably growth first, then shrinking separately.
* Expand the testing done in src/tests/sbin/resize_ffs