+ various minor cleanups
+ fix longstanding pasto where the key server preference packets are
displayed with the correct ptag information
+ up until now, there has been an asymmetry in the command line
options for netpgp(1) - whilst a file may have signature information
added to it with the "--sign" command, there has been no way to
retrieve the contents of the file without the signature. The new
"--cat" option does this (there are synonyms of "--verify-show" and
"--verify-cat") - the signature is verified, and if it matches, the
original contents of the file are sent to the output file (which
defaults to stdout, and can be set with the --output option on the
command line). If the signature does not match, there is no output,
and an EXIT_FAILURE code is returned.
+ revamped netpgp(1) to make it clear what commands are available, how
these commands relate to each other, and which commands take custom
options