default DATE is now 3 Jun 1992

guess raw file parameters, add Rate menu, call SOX to convert
file types or sampling rates that sfplay doesn't support.

add -s (short listing) option; don't print space after tab;
print data size in bytes and whether it
is a color image.

Only extract 4 bits of mode to get the file type

rewrite ismount() to compare stats of path and path/..