v0.3.0: enhancements to extras() and clean_table()

[kyleGrealis]

New Features

• New .add_p_args argument to extras() allows for passing gtsummary::add_p() arguments, such as:
  • test for specifying statistical tests for each variable (i.e., "t.test", "fisher.test")
  • pvalue_fun for formatting p-values
  • group, include, etc.
  • See ?gtsummary::add_p.tbl_summary for more information of proper usage.

Improvements

• Extended list of zero or NA value recognition used by clean_table. This fixes the funcion previously not recognizing 0 (0) for Mean (SD).