Reverse method on event readers.

Related to #87.
OMG, it *does* expose public properties, it's just that they are at the bottom of the file... :o

How about this, then:

```c#
[Theory, AutoAtomData]
public void Test(
    UuidIri id,
    AtomEventsInMemory storage,
    XmlContentSerializer serializer)
{
    var sut = 
        new FifoEvents<XmlAttributedTestEventX>(id, storage, serializer);
    var expected = 
        new LifoEvents<XmlAttributedTestEventX>(id, storage, serializer);

    var actual = sut.Reverse();

    Assert.True(
        expected.Id == actual.Id &&
        expected.Storage == actual.Storage &&
        expected.Serializer == actual.Serializer);
}
```

It passes :)