Add support for Github emojis

[Ry-DS]

It would be great if this component supports emojis from Github, notably the unique ones such as :octocat: or :electron: .
There's an api endpoint that gives the png imgs for each of these emojis, might be possible to leverage this: https://api.github.com/emojis

These are the emojis that are unique to GitHub:

[ 'atom',
  'basecamp',
  'basecampy',
  'bowtie',
  'electron',
  'feelsgood',
  'finnadie',
  'goberserk',
  'godmode',
  'hurtrealbad',
  'neckbeard',
  'octocat',
  'rage1',
  'rage2',
  'rage3',
  'rage4',
  'shipit',
  'suspect',
  'trollface' ]

[enzoferey]

Sounds like a cool feature indeed ! If you want to give it shot 👍🏻

[Ry-DS]

Sure, I'll try make a PR when I get the chance