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 didn't call it `IInterceptor` because there is also the Castle `IInterceptor`, so I called it "sink" because it represents an object, where the (Castle) interceptor delegates it's calls.