Implement support for new /homework/dueDate element in the grading.xml
file, where the due date for the assignment is specified in "yyyy-MM-dd
HH:mm" format, and each submission's date is checked against the due
date.
Add the dueDate instance variable to the GradingHelper class with a
default value far in the future, and reset to the value taken from
/homework/dueDate (if found) from the XML.
Change AssignmentResults method findSubmissionDate() to accept the
dueDate and set new instance variable daysLate to the number of days the
assignment is late (or 0 if on time). Change toString() method to report
the number of days late.
Adjust regex in findSubmissionDate() to accept the current submitted
date format (space after ':').
Add bin directory to .gitignore.