fix empty responses problem

in some cases Liftie behaved as if response was empty:
parser never completed the process, and liftie never asked for a new
status page

this change switches on response bufferring, then manually streams
response to the HTML parser

the drawback is that entire response needs to be in the memory, but that
should not be a problem for resort HTML
Merge remote-tracking branch 'origin/fix-buffered-pipe'