difference-of-squares: synchronize tests with x-common

Goal: synchronize version numbers of generic test suites in x-common
and concrete test suites in the individual tracks.

Add gitattributes file to enforce LF eol's

kindergarten-garden: add to track

fixed casing on newRowLocation variable
fixed misspelling of int

hamming: standardize starter implementation

simple-linked-list: fix array comparison in tests [Fix #567]

Code is more readable.
Use an enum instead of storing plants as strings.
Use a List rather than an Array.
More minor stuff.

Replace deprecated methods and ensure order of arguments is correct.

scrabble-score: remove unused import; clean up test formatting

space-age: standardize starter implementation

raindrops: standardize starter implementation

scrabble-score: standardize starter implementation

difference-of-squares: standardize starter implementation

acronym: standardize starter implementation

pangram: standardize starter implementation

rna-transcription: standardize starter implementation

hello-world: standardize starter implementation

Deprecate accumulate and strain

crypto-square: add hint to @Ignore annotations

bob: add hint to @Ignore annotations

binary-search-tree: add hint to @Ignore tags

binary-search: add hint to @Ignore annotations

beer-song: add hint to @Ignore annotations

atbash-cipher: add hint to @Ignore annotations