This is used by tlgsetup to prepare you input data to support
the desired column layout.
column_metadataA data frame with one row per column for each table type and six variables:
tbltypeidentifier used to group a table column layout
coldefdistinct variable values used, typically numeric
and typically a treatment or main effect variable, think TRT01PN
decodedecode of coldef that will display as a column header
in the table
span1spanning header to display across multiple columns
span2spanning header to display across multiple columns, second level
span3spanning header to display across multiple columns, third level