fix(directive-injector): Fixes for Direcive Injector.

Breaking change: Regular (application) injectors cannot construct
DirectiveInjectors (DI).  Only compilers create DI as part of view
creation process.

Deprecation: directive injector parent is now private. New public
method on dependency injector - parentGet, which allows to get through the
usual chain but skipping itself.

Component Injectors now break the resolution chain (except when called
directly.)

TestBed does not need DI in its constructor.

Internal changes:
- Application Injector reference is passed through view creation and
passed into new Directive Injector (instead of using
parentInjector.appInjector, which is wrong when used with ng-view).
- Unwind recursion from the directive injector.
- Remove EventListener from View.
- Replace DefaultDirectiveInjector with DirectiveInjector (with parent = null).
- Component visibility handled outside the visibility enum.
- Removed Shadowless and ShadowDirectiveInjector subclasses.

Closes #1111