BREAKING CHANGE:
Previously, `Directive` was the abstract base class of several directives.
Now, `Directive` is the former `Decorator`, and `Component` inherits from it.
BREAKING_CHANGE:
- The special type of `Viewport` directives is removed
in favor of a more general `Decorator` directive
- `ViewContainerRef` now no more has a default `ProtoViewRef`
but requires an explicit one when creating views.
Closes#1536
Add utility methods to convert `render.dom.DirectiveMetadata` to and
from maps. This will allow saving and restoring `DirectiveMetadata` in
the Angular 2 Transformer.
We discussed adding this as a member on `DirectiveMetadata`. Since this
is not necessary for anything except the Transformer, we decided to put
it into a separate file to avoid shipping it with the Angular 2 core
code.
vsavkin
Tobias Bosch
Tim Blasi