binary-search-tree: simplify reference implementation

nth-prime: add starter implementation

rotational-cipher: add starter implementation

* kindergarten-garden: add starter implementation

* kindergarten-garden: add constructors to starter

anagram: improve reference solution

allergies: update reference and starter implementations

bob: improve reference solution

book-store: delete .keep

binary-search-tree: remove unused import

Add topics to problem 'binary-search' #938

anagram: replace Arrays.asList with Collections.singletonList #981

* isbn: implement exercise in Java track

* isbn-verifier: Update reference solution.

* isbn-verifier: Add starter implementation.

* Add @FridaTveit 's improvements

* Add some more improvements

* saddle-points: add starter implementation.

* saddle-points: Update parameter name.

beer-song: update reference solution to package-private

* Diamond: add starter implementation.

* Add import statement

Isogram: add starter implementation

Run configlet fmt

Fix overly long UUIDs

atbash-cipher: improve reference solution

bowling: improve topics

protein-translation: add version file

Added topics for the bowling java program

POLICIES: update stub policy for nextercism

* Protein Translation: Implemented problem in Java language stream.

* Protein-translation: Update implementation with FridaTveit's suggestions.

* Fix formatting and typesafety issues.

renamed stringbuilder variable

* Add additional luhn test for fuller coverage as in #972

* Replace unnecessary test and add comment for future maintainers.

* Add link to issue #972 in Luhn tests

* Update luhn test formatting.

* Add topics to House as per #793.

* Amend 'house' topics in config.json

* Remove tag 'variables' from house topics.

* Add topic to pythagorean-triplet

* cr feedback

* Update config.json

* Update config.json

Attempt to fix space issue.