refactor(core): separate reflective injector from Injector interface

BREAKING CHANGE:
- Injector was renamed into `ReflectiveInjector`,
  as `Injector` is only an abstract class with one method on it
- `Injector.getOptional()` was changed into `Injector.get(token, notFoundValue)`
  to make implementing injectors simpler
- `ViewContainerRef.createComponent` now takes an `Injector`
  instead of `ResolvedProviders`. If a reflective injector
  should be used, create one before calling this method.
  (e.g. via `ReflectiveInjector.resolveAndCreate(…)`.

modules/angular2/src/compiler/runtime_metadata.ts

@@ -11,7 +11,7 @@ import {
 } from 'angular2/src/facade/lang';
 import {StringMapWrapper} from 'angular2/src/facade/collection';
 import {BaseException} from 'angular2/src/facade/exceptions';
-import {NoAnnotationError} from 'angular2/src/core/di/exceptions';
+import {NoAnnotationError} from 'angular2/src/core/di/reflective_exceptions';
 import * as cpl from './compile_metadata';
 import * as md from 'angular2/src/core/metadata/directives';
 import * as dimd from 'angular2/src/core/metadata/di';
@@ -27,7 +27,11 @@ import {PLATFORM_DIRECTIVES, PLATFORM_PIPES} from 'angular2/src/core/platform_di
 import {MODULE_SUFFIX} from './util';
 import {assertArrayOfStrings} from './assertions';
 import {getUrlScheme} from 'angular2/src/compiler/url_resolver';
-import {Provider, constructDependencies, Dependency} from 'angular2/src/core/di/provider';
+import {Provider} from 'angular2/src/core/di/provider';
+import {
+  constructDependencies,
+  ReflectiveDependency
+} from 'angular2/src/core/di/reflective_provider';
 import {
   OptionalMetadata,
   SelfMetadata,
@@ -185,7 +189,7 @@ export class RuntimeMetadataResolver {
 
   getDependenciesMetadata(typeOrFunc: Type | Function,
                           dependencies: any[]): cpl.CompileDiDependencyMetadata[] {
-    var deps: Dependency[];
+    var deps: ReflectiveDependency[];
     try {
       deps = constructDependencies(typeOrFunc, dependencies);
     } catch (e) {

modules/angular2/src/compiler/view_compiler/util.ts

@@ -31,8 +31,11 @@ export function getPropertyInView(property: o.Expression, viewPath: CompileView[
 
 export function injectFromViewParentInjector(token: CompileTokenMetadata,
                                              optional: boolean): o.Expression {
-  var method = optional ? 'getOptional' : 'get';
-  return o.THIS_EXPR.prop('parentInjector').callMethod(method, [createDiTokenExpression(token)]);
+  var args = [createDiTokenExpression(token)];
+  if (optional) {
+    args.push(o.NULL_EXPR);
+  }
+  return o.THIS_EXPR.prop('parentInjector').callMethod('get', args);
 }
 
 export function getViewFactoryName(component: CompileDirectiveMetadata,