Use the parent id as the location for a model.
This greatly reduces the recursive work that must be done
during move operations to keep the location accurate.
Additionally, the locationService now implements a method
`persistLocation` which can be used to persist the current object
location as it's original location.
MockLinkService.perform returns a promise for the linked domainObject.
When resolving the promise and not specifying an object to resolve it
with, it will resolve it with the domainObject that was originally
passed to it.
The entanglement bundle defines move, copy, and link actions, and
exposes them as context menu actions.
* The Move action moves an object from it's current parent to a new
parent object.
* The Copy action deep-copies an object to a new parent object.
* The Link action links an object to a new parent object.
These actions are implemented by three new services: moveService,
copyService, and linkService.
Mocks are provided for each service for easy testing of components
that depend on them.
Additionally, this bundle provides a DomainObjectFactory that simplifies
the construction of mockDomainObjects for tests.
These actions are exposed to the user as context menu options.
