TODO
====

[ ] unit tests
    - via web server
    - standalone test application

[ ] D-Bus structs
    - There are no structs in JSON. Maybe an array and the type from the
      parameter signature.

[ ] D-Bus signals
    - bridge need to save a state for each client
    - attach received signals to the state
    - client can fetch signals with a special call (?)
    - how to avoid denial of service issues?

[ ] D-Bus dictionaries with non-string keys
    - how to map these?
      - "[[key, value], [key, value]]"?
      - JSON object and use the string prepresentation of the key

[ ] calculate the D-Bus parameter signature
    - It can be derived from the introspection XML and then cached.
    - This could happen on demand on the bridge, or on the client.

[ ] dynamically create bindings from the introspection XML
    - a qooxdoo class that created objects for a service.
    - with functions for each D-Bus message
    - events/listeners for signals (?)