MainREST - release v0.3

On this release was done:

1. New version of "Agents" that scraping URLs that users set.
2. New version of "Proxy" that open the preview of URL for selecting blocks that need to scrap. Moreover the speed of getting the preview URL is increased.
3. New version of "Worker" that works each 2 hours for getting new posts from URLs that users set.
4. Add "Mailer" for sending email with confirmation and reset password links.
5. Add recaptcha for protection of bots on registration and reset password pages.
6. Add API Token for integrating posts to other systems or count post that contains searching word.
7. Add docs with description and watch requests history.
8. UI was changed and add notification module.
9. Add Billing for making payments in Crypto.