Show/Hide Empty Months feature

[cylinderStudio]

I'm suggesting a change to enable the initialization of a figure with the option to hide months that have empty/NaN values.

I'm suggesting this change to the library for situations where it would be beneficial to hide empty dates. The images below show an example of this where, in this case, the NHL hockey season starts late in the year and ends a third of the way through the next year. Lots of dates are empty which makes much of what is rendered unnecessary.

In my fork, I changed the necessary .py files. And I tried giving my fork an alternative version number and changing anything regarding the repository's requirements. (In date_extractors.py, I imported the calender library.)