ito::DObjMeta allowedTypes is wrongly implemented: Fix with next AddInInterface increment

[M. Gronle]

The object ito::DObjMeta has an argument to pass a list of allowed data types. The allowed types ito::int8, ito::float64… are not organized as bitmask, but as contiguous series of integer values, starting with 0. However, ito::DObjMeta assumes a bitmask, that can be stored in one integer. This is wrong. This has to be refactored.