inText interactivity added

Now you can use blocks (subchapters) with markdown text (rich formatting display), with sounded words.

To add sounded word use [[sounded word or phrase]] in text. And place an audio file to content/audios/intext with the same name as text. If text and file name are different, use |: [[sounded word | name_of_file_in_intext_folder]].

All markdown headers in intext chapter should have lever more than 3 (4, 5, ... ). Because levels 2 and 3 is taken by chapters and subchapters.

v1.1.0-beta

Added support for custom subchapter types related to content types.
You can set up content types in src/config/contentTypes.js (see this file for more info),
Content type will be applied to subchapter block by default = h3 (### header), or in [brackets] near the title.
### words
or
### Fruits [words]
Asset folder name should be the same as a contentType, in lower case: /content/audios/words, /content/images/words.