https://github.com/angular/angular-cli/pull/6173 added two new settings
to the serve task. The --publicHost setting is not respected as baseUrl
for protractor in the e2e-task.
With this fix, if --publicHost is set, it will be used as baseUrl for protrator.
Uses existing Protractor API to run it directly instead of using `npm run
e2e`.
Also adds support for the following flags: `--serve`, `--config`,
`--specs`, `--element-explorer`, `--webdriver-update`.
Fix#4256Fix#4478
BREAKING CHANGE: `ng e2e` no longer needs `ng serve` to be running.