Destroy dialogs when template is destroyed.
Syncing client-side local annotation document schema.
Defined all *PathFromId template helpers.

This now allows reconstructing references on the client side in a
unified manner. And displaying them in a link dialog.
Make sure usernames are unique in a case insensitive manner.
Username must never be equal to a Person _id.

Otherwise our queries for Person documents querying both _id and slug
would return multiple documents.