NSubstitute auto default values from fixture (fixes #297)

The solution is similar to what @dcastro did for AutoMoq on #302, but for NSubstitute.

There are a few differences, though:
It works with ref parameters
It won't setup void methods due to a limitation in NSubstitute that does not allow to override When..Do setups

Notes:
I had to late bind the NSubstitute methods because the signature of Returns and ReturnsForAnyArgs methods has changed a few times since 1.4.3 (had optional parameters added and return type changed). 
I added the classes that late binds the methods to the AutoFixture kernel as I though it might be helpful for someone else.

```LateBindingStaticMethodQuery```: Selects public static methods that has the same parameters of another method, ignoring optional parameters and return type.
```LateBoundMethod```: Decorates another method invoking it supplying missing optional parameters.
```GenericMethod```: Encapsulates a generic method, inferring the type parameters bases on invocation arguments.


So, you're memoizing the return value generated by AutoFixture for that specific set of arguments, so that subsequent calls using different arguments will generate new return values, correct? Is this how NSubstitute works out of the box or was this your decision?

I like the idea, and I think this kind of behaviour should be consistent across frameworks. This doesn't seem like a trivial task, but I'll submit a PR for the AutoMoq project to implement similar behaviour.