Requirements
------------

- plugable backends:

  - XML
  - flat file
  - GConf/bonobo conf
  - web registry
  - in memory (trivial?)
  - SQL backend (gda?)

- provide API to the core to load/inspect/save plugins.
- provide user/system registry
- provide combination of backends
- provide backend specific queries

user/system registry
--------------------

first query the user registry, then fall back to system registry.

API
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