Moved fake manager creation and initial configuration into the proxy generator (Part I)

This is the first part of PR #372 (we split it up into 2 PRs as mentioned there).

It solves #371 partially, namely that the default behavior is available inside the c'tor call. Therefore it also solves the bug #368 (see the `when_faking_a_class_which_calls_virtual_property_members_in_constructor` test case).
I realize that a `FakeManager` is a `ILazyInterceptionSink`, but something about calling this a `LazyFakeManagerProvider` and not mentioning `FakeManager` anywhere in the public interface strikes me as odd.