Add test for attachment upload
Remove unused import
Allow Person to be serialized
Add constructors to EMailAddress
Add default values for phone numbers & email addresses
Introduce destroyEntity
Introduce createEntity with any object
Support creation of tags (a bit special operation as the highrise api doesn't like a "tag" root element to be present in the post)
Refactor tests so that no known entities needs to be present in highrise. A test person is created and destroyed during the execution.