[MCC-114942] Fixed a possible NullReferenceException

I had fixed this during my spike but @kenyamat found it again. Now you can do:

```csharp
            var representor = new CrichtonRepresentor();

            sut.Serialize(representor);
```

Without it blowing up. Also bumped version to 0.1.5-alpha.

@kenyamat please review and merge.