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
Migration of all python code, mostly withtout chagnes. And adapting
xml files to guidelines.
On calendar.py, some changes have been perform to make the migration works :
- `_compute` method has been split into `_compute_dates`, `_compute_attendee` and `_compute_display_time`.
- remove unused method `onchange_partner_ids`, `check_partners_email`
- make `compute_rule_string` use a cache record instead of a value
dict to avoid crashes
- remove `new_invitation_token` method, and make it a default value on attendee creation
- add a default value on `day` field, otherwise the "Please select a
proper day of the month" exception is raised during the onchange
Raphael Collet