Modified bench
Added autoplot
Adopted selective nagle, update autoplot

Selective nagle switches the socket into using nagle when doing server push
for transmitting the SYN_STREAM frame of the associated content. When the
first DATA_FRAME is send, we switch back to disabled nagle (using
tcp_nodelay). Having the SYN_STREAMs transmitted with disabled nagle would
result in LOTS of tcp segments (one for each SYN_STREAM) due to our poor
implementation without buffering.