Release 0.2.3: migrate docs to readthedocs

Done:

• Migrate a docs to the readthedocs.

Release 0.2.2: clear the code

Done:

• Added coverage.
• Extended documentation.
• Refactored logic and tests.

Release 0.2.0: corner radius

Implemented:

• The corner radius supporting.

Release 0.1.0

Implemented:

• Documentation;
• Customizing 6 types of widgets;
• Redirect and callback handling of user data;
• Convenience Telegram script insertion to html.