(bug 45566) in-process caching for entities.

This provides in-process caching of entitites.
Some refactoring and moving was necessary to allow this.

In particular, the Store and StoreFactory infrastructure
(and its equivalent on the client) was changed to support
service objects that persist throughout the duration
of a request.

Change-Id: I8851c14ef2be361715483c23066e3303b011ffc0
Merge "(bug 45566) in-process caching for entities."