Display chroot names and details

Add option '-a' to operate on all chroots and '-l' to list croutonversion details.
General practice is that data output be written to stdout, and informational messages be written to stderr.  That way you can easily use the data output in a script and strip out the informational messages.

So when we output status updates, we use 1>&2, but when we output data (such as info about the chroot), we just output it to stdout.  2>&1 redirects stderr to stdout and is not needed (and shouldn't be included, as it just looks like a mistake which might get "corrected" later).