Add piping

[jwilberding]

Thanks to latitude:

Try and add support for detecting piped input on the server side:
bcp < filename
because this would allow for things like
cat filename | gzip | bcp
with the receiving end doing
bcp | gunzip > filename

[jwilberding]

http://pubs.opengroup.org/onlinepubs/007904875/functions/isatty.html