code: function arrayOfStrings(a, checkLowerCase) {
      var v = check.array(a) && a.every(check.string);
      if (v && check.bool(checkLowerCase) && checkLowerCase) {
        return a.every(check.lowerCase);
      }
      return v;
    }
docs: Returns true if given array only has strings
  @method arrayOfStrings
  @param a Array to check
  @param checkLowerCase Checks if all strings are lowercase