VitalSigns: change fields to private, add getters and setters

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@24 8153ec5e-17d7-4962-8641-23ff7c14a8d4
EmergencyRoom: add getter

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@25 8153ec5e-17d7-4962-8641-23ff7c14a8d4