add equals to Patient

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@81 8153ec5e-17d7-4962-8641-23ff7c14a8d4
change ArrayList to TreeSet in EmergencyRoom

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@82 8153ec5e-17d7-4962-8641-23ff7c14a8d4
add constructors for reading from database

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@83 8153ec5e-17d7-4962-8641-23ff7c14a8d4
add EmergencyRoom.add
start reading patients from database
implement reading visits