Imports of nats-rply command

PathSynopsis
flagPackage flag implements command-line flag parsing.
github.com/nats-io/nats.goA Go client for the NATS messaging system (https://nats.io).
logPackage log implements a simple logging package.
osPackage os provides a platform-independent interface to operating system functionality.
os/signalPackage signal implements access to incoming signals.
timePackage time provides functionality for measuring and displaying time.