Evc

Refactoring
- ref: move hardcoded kwargs_allowed param to \_\_init\_\_()
- ref get_items(): remove hardcoded args and kwargs
- ref get_first_item(): remove hardcoded args and kwargs

Misc
- Information about the pypi package has been added to the README.md
- Added 'Contents' block to the README.md and some fixes.

Misc
- add test-upload target to Makefile

Features
- added integration tests
- added automatic testing and build tools

Fixes
- reformatted source code via 'black' tool

Fixes
- fix map()

Fixes
- fixed behavior when total > 1