jest 13.0.0

• Added duration of individual tests in verbose mode.
• Added a browser config option to properly resolve npm packages with a browser field in package.json if you are writing tests for client side apps
• Added jest-repl.
• Split up jest-cli into jest-runtime and jest-config.
• Added a notification plugin that shows a test run notification using --notify.
• Refactored TestRunner into SearchSource and improved the "no tests found" message.
• Added jest.isMockFunction(jest.fn()) to test for mock functions.
• Improved test reporter printing and added a test failure summary when running many tests.
  • Add support for property testing via testcheck-js.
• Added a webpack tutorial.
• Added support for virtual mocks through jest.mock('Module', implementation, {virtual: true}).
• Added snapshot functionality through toMatchSnapshot().
• Redesigned website.