Data with default

The treatment of defaults in the case of multivalue items, i.e. like PORO or the rows in a table - have been tightened up and verified. Significant part of this PR:

1. A DeckItem has a boolean flag scalar; it is a fatal error to ask the if the default has been applied to the item as whole if it is not scalar.
2. When creating a DeckKeyword from a raw keyword we are stricter in checking that the raweyword is *finished* - i.e. has all the required records.