Remove C_SINGLE_ATTRIBUTE and C_MULTIPLE_ATTRIBUTE classes
Description
The classes C_SINGLE_ATTRIBUTE and C_MULTIPLE_ATTRIBUTE add complexity, but not much value, because both allow multiple child C_OBJECTs, since even single-valued attributes have multiples, they are just treated as possible alternatives for one item rather than for more than one.
It would therefore make sense to fold them back into the class C_ATTRIBUTE.
Impact Analysis
Should reduce some software complexity. Will require refactoring in ADL parsers and AOM implementations.
Change Description
The functionality of the classes C_SINGLE_ATTRIBUTE and C_MULTIPLE_ATTRIBUTE is folded back into C_ATTRIBUTE. This requires a flag to distinguish instances of C_ATTRIBUTE as representing multiply-valued attributes or not.
