Add gestational age to demographics
Update the gestational age model
Fix to the smoking status ontology triples
Remove the sp:unit as object definition from the ontology
Remove GestationalAgeAtBirth subclass from ontology
Adds day of death to the data model
Changes birthday to dateOfBirth
One more change to date of birth
Change dday to deathdate
Merge pull request #11 from chb/gestational

Gestational