core: update since javadoc, and add toBuilder for NameResolver results
core: update since javadoc, and add toBuilder for NameResolver results


stanley-cheung/grpc-java,grpc/grpc-java,stanley-cheung/grpc-java,carl-mastrangelo/grpc-java,carl-mastrangelo/grpc-java,grpc/grpc-java,carl-mastrangelo/grpc-java,stanley-cheung/grpc-java,grpc/grpc-java,carl-mastrangelo/grpc-java,ejona86/grpc-java,dapengzhang0/grpc-java,dapengzhang0/grpc-java,stanley-cheung/grpc-java,ejona86/grpc-java,grpc/grpc-java,dapengzhang0/grpc-java,ejona86/grpc-java,ejona86/grpc-java,dapengzhang0/grpc-java