[Bug 1325] unreachable code in sntp recv_bcst_data().

[Bug 1325] unreachable code in sntp recv_bcst_data().
[Bug 1459] sntp MD5 authentication does not work with ntpd.
Many sntp fixes from Nelson Boyard:
  1. sntp properly handles hex key strings in the keyfile, instead of
  just treating the text as binary strings.
  2. sntp handles SHA1 as well as MD5.
  3. If the key file contains more than one key, sntp can use keys
  other than the first one in the file.
  4. sntp computes the MAC using the key, then the data (was other way).
  5. sntp handles responses with extensions now.
  6. sntp implements the -b (broadcast/multicast) option.  Tested.
  The -b option takes an argument which is the broadcast/multicast
  address on which to listen for packets.  The command still requires a
  host address at the end of the command line.  This is the address
  expected to do the broadcasting/multicasting.
  7. sntp correctly handles network-order key IDs on little-endian.
  8. Eliminated a huge amount of code duplication between the sntp
  unicast and multicast code paths, creating a single process_pkt()
  function that is used for both paths after the packet is received.
  9. The -t timeout option now works with both unicast and multicast.
  Previously it worked with neither.  It wasn't coded for unicast, and
  was incorrectly coded for multicast.
  10. In unicast mode, the requests are sent MACed using the key
  specified with the -a command line option.
  11. Cleaned up indentation consistent with the predominant style in
  the files changed, namely, using tab stop characters and not spaces
  for indentation.  This way, you can set your tab stop spacing as you
  like it and the indentation looks correct.  This was not a big change.
  The files were mostly consistent before.
  12. Eliminated LOTS of blank lines.
sntp/configure.ac OpenSSL support now that sntp optionally uses it.
Escape unprintable characters in a refid in ntpq -p billboard.

bk: 4be6572580YE-GbhOQwPTAggM9bScQ