Add theme summary sheet

Usage

to_sheet_theme_summary(
  data,
  theme = NULL,
  theme_columns = NULL,
  append_to = NULL,
  wb = NULL,
  sheet = "Data",
  order = FALSE
)

data: survey data, formatted where each row is an individual and column names describe demographics or survey questions (of the format YY__ZZ, where XX is the theme and YY the question, where ' ' are replaced with '_' and '?' with 'XX'.)
theme: string containing the theme name.
theme_columns: Indices of the columns in the data for the theme
append_to: Flag (TRUE/FALSE) for whether the summary sheet is appended to a previous workbook
wb: the workbook to append the sheet to (requires append_to = TRUE)
sheet: the sheet name
order: not used

a workbook with the theme summary added