Add support for ExpressionType.Default (this is never generated by the C#'s expression trees).

This means using .NET 4.0 Expression trees, but then I've been targeting .NET 4.0
 for quite some time now, so that should be OK - it's not a breaking change and I'm not going back anyhow.
Add release note; update project tags
(minor) remove unused variables
 clean up line endings
Bump version