Fix broken type helper's declaration.

Problem: compiler doesn't parse type helpers declaration. Fails with message what id "helper" not found.
Cause: Token "reference" is identifier with idtype="_REFERENCE", "helper" is also identifier. Looks like initial closures was done before typehelper development. That is why changes in compiler/ptype didn't consider that "reference" is not unique "magic" identifier.
Fix: combine handling of "reference to" and "helper" cases.