Merge pull request #10 from NetLogo/issue-8

Fix the type string on input boxes with StrCommand. Fixes #8
upgrade slf4j, to placate VersionEye
Part 1 of refactoring BreedIdentifierHandler
Part 2 of refactoring/extending BreedIdentifierHandler
Part 3 of refactor/extend BreedIdentifierHandler
Part 4 of refactor/extend BreedIdentifierHandler
Part 5 of refactor/extend BreedIdentifierSpec
Part 6 of refactor/extend BreedIdentifierHandler
StructureParser uses BreedIdentifierHandler to find list of breed primitives
BreedIdentifierHandler describes breedHomonymProcedures to StructureParser
Refactors StructureChecker to aid understanding and ease changes.
StructureParser passes through methods named for breeds into StructureChecker
BreedIdentifierHandler case statement made more explicit
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
Interpolate all strings in StructureChecker