Make stream implement net.Conn
Make stream implement net.Conn

Signed-off-by: Derek McGowan <e1c79a582b6629e6b39e9679f4bb964d25db4aa8@mcgstyle.net> (github: dmcgowan)

jbenet/spdystream,liggitt/spdystream,dmcgowan/spdystream,ncdc/spdystream