Makefile cleanup (mark submit/clean as phony targets)
Makefile cleanup (mark submit/clean as phony targets)

cornell-cs5220-f15/demo,xzmartee/demo,xzmartee/demo,zejin/demo,amirajdhawan/demo,cornell-cs5220-f15/demo,xzmartee/demo,mwhittaker/demo,daveckman/demo,SaurabhNetra/demo,cornell-cs5220-f15/demo,mwhittaker/demo,zejin/demo,SaurabhNetra/demo,daveckman/demo,daveckman/demo,amirajdhawan/demo,SaurabhNetra/demo,zejin/demo