Flush stdout after each PT line.

This hadn't been causing a problem when websocket-server was run
directly by Tor, but I tried running websocket-server as a shell
subprocess, and the shell wasn't seeing its PT negotiation.
Move max message size to a constant.
Increase maximum message size to 64 KB.

Testing obfs3-in-websocket was reliably failing at 50% bootstrapped with
a message of about 30 KB.
Fix the safe_str comment.

Found by Arlo.

https://trac.torproject.org/projects/tor/attachment/ticket/9170/0001-Don-t-log-IP-addresses-by-default-in-flashproxy.js.patch
Don't log IP addresses by default in flashproxy.js

Adds an undocumented query string parameter, unsafe_logging.

See #9170.
Small style change.
ChangeLog for IP scrubbing in the proxy.
Add HEADLESS global indicating whether we have a DOM.
Support for running flashproxy.js in node.js
Make package.json's version independent of Makefile's.

Until we have a way to keep these numbers in sync automatically, I
prefer to have them independent.
Not symlinked anymore.
Debian testing doesn't have nodejs, only unstable.
ChangeLog for standalone Node.js proxy.