TODO
    To-do list for Class::Tie::InsideOut and Tie::InsideOut

  Enhancements
    *   Add an equivalent mk_accessors function akin to what Class::Accessor
        does.

    *   Change FIRSTKEY and NEXTKEY methods in Tie::InsideOut so that they
        only show methods that the caller has access to.

    *   Add an option so that a default exception handler or callback can be
        given rather than dieing when a key is accessed outside of its
        namespace. Then one can provide a map of field names to methods to
        call.

  Tests
    *   Verify that deserialization into a different namespace causes an
        error.

    *   Add better tests for FIRSTKEY and NEXTKEY methods in Tie::InsideOut.

    *   Add the usual "kwalitee" tests.