Add ability to list the contents of a directory selected for undeletion

This directory browsing only applies to the first level under the
selected directory (you can't drill down the subdirectories).  It will
list all files and directories in alphabetical order, along with their
file sizes and modification timestamps.

Also, additional sanity checks were added to both the directories
(apparently empty directories skipped) and files (those that fail "stat"
are left off).  It turns out that some unrecoverable files and
directories were listed as candidates, even ahead of better older
versions so this improves the changes of recovery.