Adds the new flag `--build-optimizer` (`--bo`), usable only with `--aot` (or `--prod` since it auto enables `--aot`).
This feature is experimental, and may not work correctly on your project. Should it work, total bundle size should go down. Savings are heavily dependent on the project.
See https://github.com/angular/devkit/tree/master/packages/angular_devkit/build_optimizer for details about all the optimizations applied.
Usage: `ng build --prod --build-optimizer`. Disabling the vendor chunk has been shown to improve total savings, and is done automatically when `--bo` is specified unless `--vendor-chunk` has a value.
Please let us know if using `--build-optimizer` breaks your project so we can improve it further. Repos are very welcome.
