allow ogginfo to read from stdin

[AntiSol]

I'd love for ogginfo to be able to read ogg data from stdin. oggenc and oggdec will happily use stdin/stdout using a hyphen as the filename as you'd expect, but ogginfo doesn't seem to be able to do the same. I looked through the man page and did a couple of web searches and I don't see any way to get ogginfo to read from stdin.

As a workaround I'm able to write my ogg data to a temporary file and then tell ogginfo to look at that, but this lacks elegance:

fn=`mktemp /tmp/oggdataXXXXXXX.ogg`
echo $OGGDATA > $fn
inf=`ogginfo $fn`
rm $fn

rather than:

inf=`echo $OGGDATA | ogginfo`

thanks for your time :)