Add --print as an alias for -P, to match tcpdump.

Add --print as an alias for -P, to match tcpdump.

tcpdump just got a --print option, which causes packet information to be
printed even if the raw packets are being saved to a file with -w.  We
have -P for the same purpose; make --print another name for it.

While we're at it:

	document --help and --version;

	just speak of -P/--print as causing printing even of the packet
	details, even though -V forces printing with -w, for consistency
	with how --print is documented for tcpdump;

	fix the description of -h/--help.

Change-Id: Idf650a202a09a2d1682edbd9d76123f1b1412b55
Reviewed-on: https://code.wireshark.org/review/23888
Reviewed-by: Guy Harris <guy@alum.mit.edu>