simple HTTP transport

arturo started coding a simple HTTP transport for obfsproxy.

It needs love before it's ready, but it's a good start.

(https://github.com/hellais/obfsproxy.git, branch httpproto) https://github.com/hellais/obfsproxy/tree/httpproto

(It's not a complex HTTP transport. It won't pass through HTTP proxies, and it does not do valid HTTP. Still, it might force censors to parse HTTP if they want to block it.)