Improve responder component

[oubiwann]

This component responds to the events published by the watcher component. It will dispatch specific functions upon published event type/s, but with controls/limits appropriate for computationally expensive or time-consuming handlers. This is delay/batching mechanism is intended to prevent handler execution floods, keep rapid-fire changes from bogging down the system.

The first half of this work was done in 0.6.0 (see #49)

The following tasks remain:

• Add timeout-tracking capability
  • Defining a countdown protocol
  • Define countdown behaviour functions
  • Extend the component to use the protocol and behaviour
  • Implement state tracking with async go loop
• Add channel logic to fire after the countdown (timeout) has completed
• If an additional request is received before during the countdown and be fore the firing of the handler, re-do the countdown -- only fire the handler if no new events have made a request during the countdown (timeout) window