Add #delete_blanks and #delete_nils to Array
Add #delete_blank_paths
Add tests for #delete_blank_paths
Add Array#find_path
Add Hash#find_path
Switch to returning [k] instead of Array(k)
Add specs with nil keys and Array keys
Fix bug in all shared methods related to accessing keys that are Arrays.

  Previously all methods could not properly store or access Hash keys that
  are Arrays.  Flattening the args one level if called from itself will
  resolve the issue.

  Example input: {}.store_path([1,2],3)
  Prior result:     {1 => {2 => 3}}
  Corrected result: {[1, 2] => 3}}
No longer possible to test arg modification here.

Hash tests on argument modification should be sufficient