* 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
* Improve resilience against null fields
* Fix client processMessage when handling error
* Improve both client and server resilience against fields and elements with null value
* Upgrade rpc router internals
* use new chronos asyncraises
* Fix style mismatch
* Fix nim v2 compilation error
* Addresing review
* Remove unnecessary custom serializer and let the library do the work
* fix error message
* Update readme.md
The users will be now able to write RPC handlers returning the
distinct type `StringOfJson`. This will bypass any use of the
standard library's JsonNode type and its serialization routines.
The change was motivated by the integration of JSON-RPC in
status-im/nim-beacon-chain where most of the data types cannot
be handled by Nim's std lib or json-rpc's jsonmarshal module.
