trimming trailing blanks is too hard; the last revision handles most of the

trimming trailing blanks is too hard; the last revision handles most of the
cases -- the one I quit on is where you have:
"%06.6_ao "  12/1 "%3o "
"\t\t" "%_p"
"\n"
You'd have to read-ahead and figure out what's going to be printed from
future format strings to know if the current line should be blank padded.

SCCS-vsn: usr.bin/hexdump/bpad.c 5.2
SCCS-vsn: usr.bin/hexdump/display.c 5.2
SCCS-vsn: usr.bin/hexdump/hexdump.1 5.2
SCCS-vsn: usr.bin/hexdump/hexdump.h 5.2