* 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.