Serializer: Code Cleaning
Serializer: Code Cleaning

1. Removing attr_writer from `:object` - not used
2. Removing setting of `@object - object`, in `serialize_to_json` - this will happen if needed in C extension side (see serialize method fields)
3. Remove checking if writer exists (writer ||=), this was used in the old version Panko where ruby did the serialization.  
yosiat/panko_serializer,yosiat/panko,yosiat/panko_serializer,yosiat/panko,yosiat/panko_serializer