Convention-based type resolver for Data Contract serializer

Resolves #94.
If we do that, then the usage would be:

```c#
var sut = 
    new DataContractContentSerializer(
        DataContractContentSerializer.CreateTypeResolver(assembly));
```

Or

```c#
var resolver = DataContractContentSerializer.CreateTypeResolver(assembly);
var sut = new DataContractContentSerializer(resolver);
```

I don't know...

I thought that `Create` would make it easier to create a new `DataContractContentSerializer` instance...