Description
DateLexicoder incorrectly orders dates before 1970 at the end of all other dates.
Therefore, the order was correct for all dates if the user only wrote dates before 1970, or only dates after 1970, but not if they did both.
The DateLexicoder should be fixed to store using a signed LongLexicoder internally, instead of the ULongLexicoder that it used before.