Alertapi

Bug fixing

Renaming
`Client` has renamed to `APIClient`
`app` in event objects has renamed to `api`

Documentation
Added documentation [View Here](https://alertapi.readthedocs.io/en/latest/)

Flaw fixing
`aiohttp_sse_client` package was not added in `requirements.txt` — fixed.
Added docstring to `static_map` method