Major refactor.

- 'processRequest' to take care of setting generic header for
  JSON-API/Fortune.js
- 'processRequest' also takes care of converting message reply to JSON
- Every operation request now has callback.
- Handling of callbacks after request ( regular as well as
  exceptional/errorneous scenario ) is left to the caller.
- Helper functions ( to display pretty tables ) are available in library as they
  are still reusable.
CLI option name changed. From 'number' to 'id'.

- Changed name is more representative of the argument we will supply.