send: flush stdout after displaying code
send: flush stdout after displaying code

Fixes https://github.com/warner/magic-wormhole/issues/108

Apparently python defaults to buffering stdout when not outputting to
the terminal. It would be better IMHO if every line of stdout were
autoflushed, but based on
http://stackoverflow.com/questions/107705/disable-output-buffering
there's not a really good way to accomplish that in python.

warner/magic-wormhole,warner/magic-wormhole,warner/magic-wormhole,warner/magic-wormhole