Added methods to set/create a RFC 4122 UUID as the uid field.
Fix #42 : Properly handle UIDs on Contacts.
* Changed primary key to UID type. Either preserve UID on storage or create
new one if empty. Updated queries to reflect change.
Fix #40: Eliminate filterIDsByKind(..).
* Refactored to select in one step via join.
* Updated configured queries.
* Tweaked tests during debugging.