Added month calplot

[daviddavo]

I created a plot that works by month instead of day by day

• [x] Create tests

[brunorosilva]

That's a very nice improvement, I'll merge it and refactor some parts of it in the future

[daviddavo]

Thank you for merging!

Feel free to contact me if there is something you don't understand, and let me know when this change is available on pypi