Automatically reconcile XML<->ActivityType/RelationshipType

The XML definition of a CaseType includes the names of activity-types and relationship-types. We should automatically scan these and update the list of activity-types/relationship-types in the DB, e.g.

• (High priority) If a new activity-type appears in XML, then add it to DB
• (Medium priority) If an old activity-type disappears (and isn't otherwise used by activities), then remove it
• (High priority) If a new relationship-type appears in XML, then add it to DB. (The RT will need names for the two sides of the relationship. For the second side, simply take the first name and append "is"; "Case Manager" => "Case Manager is").
• (Medium priority) If an old relationship-type disappears (and isn't otherwise used), then remove it.