Add todoMVC example with React

[mikhin]

Hi there!

There are still things which needed to be done:

• Add hot-reload to the server part of application;
• Add i18n for the 1 items left element;
• Check and improve a11y of application;
• Need to remove todo if it's text become empty;
• Add text selection when todo become editable;
• Add beauty style for error pages
• Add reactive state for toggle action dependent of state of all todos

I would like to add these things in this PR in next week, If I catch it in time, or it can be done in next PRs.

[ai]

Looks good for now. I will merge it tomorrow, when I will be at home.