Add acceptedStudentsCSVExport function to stats.py script. This funtion is used to generate CSV with all accepted students. It still needs some work and I left TODOs there. I also added helper function for saving data to CSV, which can be reused for other kinds of reports.

from query import *
from subqueries import *
from where import AND, OR
from datastructures import EmptyResultSet

__all__ = ['Query', 'AND', 'OR', 'EmptyResultSet']