Update UML Class diagram META

[finger563]

Need to update to support:

• Better specification of complex data types (such as arrays of enumeration types)
• Best way to specify pointers / instances of complex data types in classes
  • Should we keep composition / aggregation / dependency the same as UML spec (which is too general)?
• Best way to specify visibility for relationships (e.g. public inheritance, friend classes / methods, etc.)

Should help facilitate the generation of usable code from the model.

[finger563]

Also need to look at better way of specifying return types for methods