message: use strict for eval, to prevent leaking of evaled information
diff: @@ -19,8 +19,11 @@ export class CodeKataValidationService {
  };
  try {
  + (() => {
  + 'use strict';
  // tslint:disable-next-line:no-eval
  result = eval(codeToTest);
  + })();
  } catch (e) {
  const err = e.constructor('Error in evaled Script:' + e.message);
  err.lineNumber = e.lineNumber - err.lineNumber;
  