add readVitalSigns and readSymptoms to Database

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@89 8153ec5e-17d7-4962-8641-23ff7c14a8d4
fix errors in Database class

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@90 8153ec5e-17d7-4962-8641-23ff7c14a8d4
fix issues in other classes

git-svn-id: https://markus.cdf.toronto.edu/svn/csc207-2014-09/group_0909@91 8153ec5e-17d7-4962-8641-23ff7c14a8d4