* 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