* remove redundant gcsafe/raises
* rework async raises to chronos 4.0 where this was not yet done
* streamline logging between http/socket/ws
* don't log error when raising exceptions (whoever handles should log)
* debug-log requests in all variants of server and client
* unify ipv4/ipv6 address resolution, with preference for ipv6
* fix server start so that it consistently raises only when no addresses
could be bound
