fix(application): set injector property when bootstraping the app

Closes #1391
fix(travis): BUILD_LEADER is not available in build.sh

Replace with check that TRAVIS_JOB_NUMBER ends at .1.

Closes #1362

Closes #1393
feat(directive-injector): detect and throw on circular deps

The maximum depth for depth for dependency construction within a single
injector is set to 50.

No performance degradation observed on tree benchmark.

Closes #1364
feat(components): implement css encapsulation for transcluding components

* Extract ComponentCssLoader so it can be shared by ShadowDomComponentFactory and TranscludingComponentFactory
* Provide a built-in implementation of WebPlatformShim using css_shim
* Implement a CSS transformer similar to the one provided by Platform.JS
* Rename EventHandler into ShadowBoundary