incidence2 2.0.0

Version 2.0.0 is a major, breaking release of incidence2. We have undertaken a
significant refactor that both simplifies the underlying code base and makes the
user interface more consistent and robust. Although the main changes are
highlighted below, users are strongly advised to read through the accompanying
documentation and vignettes.

breaking changes

• We no longer support NSE (e.g. tidyselect semantics) within the package. Our
  motivation for removing support for NSE are both the complexity it can bring
  to the underlying code (making long term maintenance harder) and the
  complexity it can cause for other users / developers who want to build on
  top of incidence2.

• new_incidence(), validate_incidence(), build_incidence(), get_n(),
  get_interval(), get_timespan() and facet_plot() are now defunct and
  will error if called.

• complete_counts() is now renamed complete_dates() and gains two new
  parameters, expand and by. If expand is TRUE (default) then
  complete_dates() will attempt to use
  function(x) seq(min(x), max(x), by = by) to generate a complete sequence of
  dates.

• The incidence() function now always returns output in long format with
  dedicated columns for the count variables and values (set by arguments
  count_names_to and count_values_to).

• incidence() is now less flexible in what it can accept for the interval
  argument. For more complex date groupings users are encouraged to perform
  their require data transformations prior to calling incidence().

• The default plotting of incidence objects as been greatly simplified. Sensible
  defaults have been chosen to enable a quick visual overview of incidence
  objects but users are advised to call ggplot2 directly for more bespoke
  plotting.