Deleted the 'Dao.Evaluator.AST_Struct' node from the 'Dao.Evaluator.AST_Object' data type.  Constructing trees is now evaluated as a special case of the 'Dao.Evaluator.AST_Init' and 'Dao.Evaluator.InitExpr' nodes.
        Also, corrected a bug in the AST specification: I had removed the preceding comments from the optional item in the 'Dao.Evaluator.AST_OptObjList' because I had forgot the reason it had to be there. This node is only used in 'Dao.Evaluator.AST_Init' constructors. There must be an optional whitespace after a closing round-bracket and before an opening curly-bracket. I have put back the optional comments in the 'Dao.Evaluator.AST_OptObjList' to correct this bug.