Make Invoker a subtype of Function1

The use case is being able to easily 'untuple' JdbcQueryTemplate like this:

val targetToSourceQuery = Function.untupled(for {
    (targetNamespace, targetId) <- Parameters[(String, String)]
    ct <- CurrentTransformations
    mapping <- TransformationIdMappings if ct.statusId === mapping.statusId &&
                 mapping.targetId === targetId &&
                 mapping.targetNamespace === targetNamespace
} yield (mapping.sourceNamespace, mapping.sourceId))

Cheers