refactoring the mechanism to identify a persona
removing the 'about' on 'PlaceDescription' per FamilySearch/gedcomx#220
Merge branch 'master' into persona-flag
updating persona-flag to reflect latest proposal
Merge branch 'place-description-identifiers'

Conflicts:
	gedcomx-model/src/main/java/org/gedcomx/conclusion/PlaceDescription.java
support for Document 'textType' attribute