init react version

因为没调教好相对路径，暂时把 MyCardProduct.png 移至根目录

Add leading slash to appAssets variable
closes #329

Blocked on https://github.com/angular/in-memory-web-api/pull/86

As per https://github.com/zloirock/core-js/issues/152, `core-js` already includes `reflect-metadata`.

When https://github.com/angular/protractor/pull/3848 is ready it should fix the webdriver types issues, and the pinning can be reverted.

The zone.js problem is being tracked on https://github.com/angular/zone.js/issues/554.

Fix https://github.com/angular/quickstart/issues/325

 This update ensures examples get "cold" observables from `Http` when using in-mem-web-api

chore: update to 2.3.0

closes #301

* remove `exclude` clause from `tsconfig.json`; it was just confusing people
* karma.config + karma-test-shim can handle multiple spec source paths (issue #294)
* cosmetic `app.component.spec.ts` changes
* cosmetic `karma.config.js` changes

The package is not listed in `package.json` and https://github.com/angular/angular.io/pull/2803 will contain instructions to add it manually.