StructuredLabels using DynArry<StructuredData*> and StructuredData refactoring extending SGRefObject

* Introduced new class `SGRefObject`: Simply a stripped copy of `CSGObject`, but without parameter framework 
* Changed base class of `StructuredData` from to `SGRefObject`
* StructuredLabels now using `DynArry<StructuredData*>` instead of `DynamicObjectArray`, because the latter can only hold `CSGObjects`
* (updated a lot of files to reflect name changes, including SWIG mappings)