Create PreferencesBuilder

[micheljung]

In test classes, we quite often mock a Preferences tree.
It would be easier if we created one builder that builds up the whole object tree (either as a Mock object or as a "real" object, I guess the real object would be sufficient).

Then, replace all mocked Preferences with that builder.

---

Want to back this issue? Post a bounty on it! We accept bounties via Bountysource.