Added IfNotNull overloads for nullable structs, although I couldn't get actual overloads to work so I had to rename them.
Added a helper for writing object lists to XmlWriter.
Added a helper for reading object lists from XmlReader.
Added a MoveToElementByName helper to XmlReader.
Helpers for serializing ISO 8601 datetimes.  Needs some tests.
Version 1.5.1.