function Remarkable(preset, options) {
  if (typeof preset !== 'string') {
    options = preset;
    preset = 'default';
  }

  if (options && options.linkify != null) {
    console.warn(
      'linkify option is removed. Use linkify plugin instead:\n\n' +
      'import Remarkable from \'remarkable\';\n' +
      'import linkify from \'remarkable/linkify\';\n' +
      'new Remarkable().use(linkify)\n'
    );
  }

  this.inline   = new ParserInline();
  this.block    = new ParserBlock();
  this.core     = new ParserCore();
  this.renderer = new Renderer();
  this.ruler    = new Ruler();

  this.options  = {};
  this.configure(config[preset]);
  this.set(options || {});
}
The main `Remarkable` class. Create an instance of
`Remarkable` with a `preset` and/or `options`.

@param {String} `preset` If no preset is given, `default` is used.
@param {Object} `options`