Feature/emoji-hasEmoji

[smeijer]

Add Emoji.hasEmoji method. This PR is build upon #53, so either that one should be merged first, or this one should be refactored.

Readme should also cover Emoji.hasEmojiByName and Emoji.hasEmojiByCode, but like I wrote in #53, I think the readme could use a general makeover. So I wanted to postpone that change, to keep the upcoming release more agile. Emoji.hasEmoji is covered by the readme update.

This PR turnes the tests below green:

describe('hasEmoji', function() {

    it('Should be able to check a emoji by :name:', function() {
      var result = emoji.hasEmoji(':heart:');
      result.should.equal(true)
    });

    it('Should be able to check a emoji by name', function() {
      var result = emoji.hasEmoji('heart');
      result.should.equal(true);
    });

    it('Should be able to check a emoji by code text form)', function() {
      var result = emoji.hasEmoji('❤');
      result.should.equal(true);
    });

    it('Should be able to check a emoji by code in variant form', function() {
      var result = emoji.hasEmoji('❤️');
      result.should.equal(true);
    });

    it('Should return false for unknown emoji names', function() {
      var result = emoji.hasEmoji(':pizza-kiss-coffee:');
      result.should.equal(false);
    });

    it('Should return false for unknown emoji codes', function() {
      var result = emoji.hasEmoji('🍕❤️‍💋‍☕');
      result.should.equal(false);
    });

  });

[omnidan]

thank you so much 😁