Changed input file grades.in

Using G's sample.in but without the extra score for Wadia.
studentScores // fixed 'quiz'/'qz' & an inappropriate "is not"

The "is not" was corrected to '!='
studentScores // EOFError won't work for this application.

In fact, the only way EOF is relevant to a Text IO object in Python 3
is if its reached by an iterable object. Funny huh?
Once a Text IO object reaches EOF, it will return an empty character,
so I'm going to try that as a surrogate EOF check.