Written the consumer for emojis expansion.

  There is no code to actually do that, but the API I've written
 in the caller looks sane.
  Added HTML::Emojis (new module).
  Added emoji-images.
  The easter-egg documents emojis support.
  Added header.
Merge pull request #3 from skx/emojis

We should have emojis support.  This closes #2.