refactor(core): introduce ComponentFactory.

Each compile template now exposes a `<CompName>NgFactory` variable
with an instance of a `ComponentFactory`.
Calling `ComponentFactory.create` returns a `ComponentRef` that can
be used directly.

BREAKING CHANGE:
- `Compiler` is renamed to `ComponentResolver`,
  `Compiler.compileInHost` has been renamed to `ComponentResolver.resolveComponent`.
- `ComponentRef.dispose` is renamed to `ComponentRef.destroy`
- `ViewContainerRef.createHostView` is renamed to `ViewContainerRef.createComponent`
- `ComponentFixture_` has been removed, the class `ComponentFixture`
  can now be created directly as it is no more using private APIs.

modules/benchmarks/src/tree/tree_benchmark.ts

@@ -1,6 +1,5 @@
 import {bootstrap} from 'angular2/platform/browser';
 import {
-  Compiler,
   Component,
   Directive,
   ViewContainerRef,
@@ -96,7 +95,7 @@ export function main() {
           var injector = ref.injector;
           appRef = injector.get(ApplicationRef);
 
-          app = ref.hostComponent;
+          app = ref.instance;
           bindAction('#ng2DestroyDom', ng2DestroyDom);
           bindAction('#ng2CreateDom', ng2CreateDom);
           bindAction('#ng2UpdateDomProfile', profile(ng2CreateDom, noop, 'ng2-update'));