The API of `Registry` has been modified as follows:
- `Registry(name)` returns the registry of the given database
- `Registry.new(name)` forces the creation of a new `Registry` object
- `Registry.delete(name)` discards the given registry
- `Registry.delete_all()` discards all registries
- `registry.setup_signaling()` initializes the signaling for `registry`
- `registry.check_signaling()` returns an up-to-date `registry`
- `registry.signal_registry_change()` notifies that `registry` has changed
- `registry.signal_caches_change()` notifies potential cache invalidation
Raphael Collet
a7445b4053