Fix ScalaStyle and comment
Pour syntactic sugar on StructureParser
BreedIdentifierHandler uses collect over filter -> map
Use String Interpolation for matchesBreedName
Convert Helper to case class, remove custom extractor
Major refactor of BreedIdentifierHandler:

- Rename Helper to BreedPrimSpec
- Introduce three case classes of BreedPrimSpec, one for each type of breed:
  - TurtlePrimitive
  - DirectedLinkPrimitive
  - UndirectedLinkPrimitive
- Remove BreedType
- Remove Spec
- Use case class constructors instead of methods to create the list of breed primitive specifications