Fixed QueryInterface for the instance method of a Mocked Interface.

QueryInterface will now work for all implemented interfaces off the object/interface returned by Instance.
Only thing left to implement is the Verify<T> and VerifyAll methods. These will verify the setup of the specific implementation or all setups calls.
TMock<T>.Implement<I>, TMock<T>.Setup<I>, TMock<T>.Instance<I>, and TMock<T>.Verify<I> have all been fully implemented.

This change allows the implementation of multiple interfaces on the one mock. The interfaces which are returned by the mock via the "instance" function will support all "implemented" interfaces set on the TMock.