Simpler dropbox submissions
More complex late penalties are now supported

Any number of dates and late penalty multipliers can be specified ---
socrates will maximize the late penalty given the list of dates,
multipliers, and the modification date of a submitted file. For
example, if {0.10: A, 0.20: B, 1.00: C} is specified in the criteria
file, socrates selects A if the modification date comes after A and
before B. If the modification date comes after C, a multiplier of
1.00 is used.