Release v1.0.0 - transaction studies

actxps 1.0.0

The actxps package now contains support for transaction studies.

• The add_transactions() function adds transactions to exposed_df objects.
• The trx_stats() function summarizes transaction results and returns a
  trx_df object.
• New transaction summary (trx_df) S3 methods were added for for autoplot()
  and autotable().
• The exp_shiny() function was updated to support transaction studies.
• New sample data sets were added with transactions (withdrawals) and
  sample policy values (account_vals). These are meant to be paired with
  census_dat.
• Added vignette("transactions").

Other changes

• A new family of functions were added to calculate policy durations. These
  include pol_interval() (a generic version), pol_yr(), pol_qtr(),
  pol_mth(), and pol_wk(). See vignette("misc").
• Several updates were made to the as_exposed_df() function to include
  stricter input requirements and helpful error messages.
• S3 methods for several dplyr functions were added for exposed_df objects to
  ensure class persistence, especially on grouped data frames. These include:
  group_by() and ungroup(), filter(), arrange(), mutate(), select(),
  slice(), rename(), relocate(), left_join(), right_join(),
  inner_join(), full_join(), semi_join(), and anti_join().
• The conditional formatting for color in autotable.exp_df() was updated to
  be consistent across like columns.
• The pol_val column in census_dat was renamed to premium.