XD-2015 UI end-to-end (E2E) tests do not work

* Made the documentation (README.md) clearer regarding issue `Could not find chromedriver...`
* Due to the recently introduced addition of polling the E2E tests were partially broken also. Add `browser.ignoreSynchronization=true` to the tests as described at https://github.com/angular/protractor/issues/49
This should be in single-quotes.