PHILADELPHIA — A group of student protesters at the University of Pennsylvania ended a nearly six-week encampment on the College Green this weekend after they stormed Franklin Field during halftime of the Penn-Yale football game. The students, who belong to a group called Fossil Free Penn, have been calling on the university to help low-income residents who are being displaced from the neighboring University City Townhomes, further dissociate from fossil fuel companies, and make payments to the city in lieu of taxes. Nineteen people, 17 of them students, were arrested in the football field tak…