Evaluate InterventionStudy->AppropriateSex maxOccurs attribute

InterventionStudy->AppropriateSex is the only xsd element with a maxOccurs attribute that is not 1 or unbounded. In 2.0 final maxOccurs = 2. Since SexType has been changed in 2.0 final to include 'Not Selected' as an enumeration value, this property should be reanalyzed to determine if this needs to be a collection or if a single property value can capture the data for the model.

1/21/16 - meeting - Decided to change to unbounded.