#41 - don't disconnect websockets if 'receiver' doesn't come back in 5 seconds

Timeout mechanism is broken with regard to websockets. cowboy process might be overloaded by incoming messages (And session not being able to pick them up quickly enough). If that happens, it's quite likely that session process will receive a timeout after 5 seconds of not having the 'reply' call. This seems to be less of a big deal for non-ws transports as they don't neccesairly come via a signle bottleneck process - receiver is different than sender.