Implementing io.Sound.toString() and isEqual() methods.
Adding newly created io.Graph instances to doob.assets and implementing io.Graph.toString() and isEqualTo() methods.
Adding newly created io.Chain instances to doob.assets and implementing toString() and isEqualTo() methods.
Adding SoundPattern to doob.uniqueNames.
SPEC: uniqueNames.SoundPattern & uniqueNames.Gain.
Adding a unique name to each SoundPattern instance.