Implement deserializing into enums

[xPaw]

ValveKeyValue/ValveKeyValue/ValveKeyValue.Test/Text/ObjectSerializationTypesTestCase.cs

Lines 34 to 36 in b61e276

	// TODO: Deserializing enums does not work yet
	//var deserialized = KVSerializer.Create(KVSerializationFormat.KeyValues1Text).Deserialize<DataObject[]>(text);
	//Assert.That(deserialized, Is.EqualTo(dataObject));

System.NotSupportedException : Converting to SomeEnum is not supported. (key = VEnum, type = Int32)

It probably just needs to cast as to the backing type.