fixed issue where stringToTokens is not being exported correctly

Author: mientjan

example/package.json

@@ -9,6 +9,7 @@
     "test": "jest"
   },
   "dependencies": {
+    "linkify-it": "^2.0.3",
     "markdown-it-checkbox": "^1.1.0",
     "prop-types": "^15.6.1",
     "react": "16.3.1",

src/index.js

@@ -5,7 +5,7 @@
 import React, { Component } from 'react';
 import PropTypes from 'prop-types';
 import { View } from 'react-native';
-import { parser, stringToTokens } from './lib/parser';
+import parser from './lib/parser';
 import applyStyle from './lib/util/applyStyle';
 import getUniqueID from './lib/util/getUniqueID';
 import hasParents from './lib/util/hasParents';
@@ -17,7 +17,7 @@ import MarkdownIt from 'markdown-it';
 import PluginContainer from './lib/plugin/PluginContainer';
 import blockPlugin from './lib/plugin/blockPlugin';
 import { styles } from './lib/styles';
-
+import { stringToTokens } from './lib/util/stringToTokens';
 /**
  *
  */

src/lib/parser.js

@@ -12,7 +12,7 @@ import groupTextTokens from './util/groupTextTokens';
  * @param {AstRenderer} [markdownIt]
  * @return {View}
  */
-export function parser(source, renderer, markdownIt) {
+export default function parser(source, renderer, markdownIt) {
   let tokens = stringToTokens(source, markdownIt);
   tokens = cleanupTokens(tokens);
   tokens = groupTextTokens(tokens);