Editor.js dons't work in Firefox 49 and many other not fresh browsers.

In the main page you mention about supporting browsers, and in list Firefox is supported from 18+.
Editor.js dons't work in Firefox 49 and many other not fresh browsers.
Reproduced on the project main page (https://editorjs.io/)
LOG:

```
GET https://editorjs.io/dist/main.css [HTTP/1.1 200 OK 0ms]
The resource at “https://mc.yandex.ru/metrika/tag.js” was blocked because tracking protection is enabled.[Learn More]editorjs.io
TypeError: hawk.init is not a function
[Learn More]editor:1:1
ModuleDispatchercodex.bundle.js:15
Module «pluginsFilter» initializedcodex.bundle.js:15:1454
Module «editorLanding» initializedcodex.bundle.js:15:1454
Resource loading JS highlight: timer startedcodex.bundle.js:6
Resource loading CSS highlight: timer startedcodex.bundle.js:6
Cannot find element with id vk_groupscodex.bundle.js:29:18337
Resource loading JS highlight: 265.82mscodex.bundle.js:6
Resource loading CSS highlight: 266.66mscodex.bundle.js:6
Code Styling is readycodex.bundle.js:29:18866
SyntaxError: missing = in const declarationeditor.bundle.js:3:284891
GET
https://editorjs.io/dist/main.css [HTTP/1.1 200 OK 0ms]
Error: codex.bundle.js:1:707
Use of getPreventDefault() is deprecated. Use defaultPrevented instead.
```
Thanks!