creation date

[pnrobinson]

The creation date field of "Term" is not being populated.
Goal is to use this field to count new terms, something like this:

Term term = opt.get();
Optional<Date> opt2 = term.getCreationDate();
if (opt2.isPresent()) {
    Date creationDate = opt2.get();
    if (creationDate.after(cutoffDate)) {
       some_counter++;
    }
}

This is a non-essential field for many kinds of analysis, but we should either remove the accessor or implement it.