NEW FEATURE: Add an overall column easily.
@ndevln contributed the addOverall option (see the pull request), which add the overall column side-by-side with sratified columns when creating a table object. See the help of CreateTableOne and svyCreateTableOne.
addOverall(optional, only used if strata are supplied) Adds an overall column to the table. Smd and p-value calculations are performed using only the stratifed clolumns.