cleanup(DI): clean up visibility decorators

BREAKING CHANGE:
    Replace @Ancestor() with @Host() @SkipSelf()
    Replace @Unbounded() wwith @SkipSelf()
    Replace @Ancestor({self:true}) with @Host()
    Replace @Unbounded({self:true}) with nothing
    Replace new AncestorMetadata() with [new HostMetadata(), new SkipSelfMetadata()]
    Replace new UnboundedMetadata() with new SkipSelfMetadata()
    Replace new Ancestor({self:true}) with new HostMetadata()

modules/angular2/annotations.ts

@@ -5,7 +5,7 @@
  * Annotations provide the additional information that Angular requires in order to run your
  * application. This module
  * contains {@link Component}, {@link Directive}, and {@link View} annotations, as well as
- * the {@link Ancestor} annotation that is used by Angular to resolve dependencies.
+ * the {@link Host} annotation that is used by Angular to resolve dependencies.
  *
  */