Do not encode chunk, just write as is.

Encoding as 'utf-8' does not work well on `chunk` as it is a fixed stream of bytes. Maybe see also this article about [Python, terminals and encoding](http://lucumr.pocoo.org/2014/5/12/everything-about-unicode/).

I get errors like this, when starting a bash with `fig run` and pressing `ö` for example:

    DEBUG:fig.cli.socketclient:'ascii' codec can't decode byte 0xc3 in position 0: ordinal not in range(128)

Without encoding it works fine.