#4 documentation

We need to discuss which functions need to be exported (i.e. which functions need to be available for the package user) and properly document them (see how that works in read_all for example).

Also some nicer vignettes should be available. One can use vignettes/funwithdata.Rmd as an example.

all exported functions are documented

Könnt ihr noch mal bei der Dokumentation von word_usage_by_date schauen?

word_usage_by_date is fixed. We could add some example code in analyze.R for the documentation, but that is low prio.