refactor(core): add Query.read and remove DynamicComponentLoader.loadIntoLocation.

This adds the feature for `@ViewChild`/`@ViewChildren`/`@ContentChild`/`@ContentChildren` to define what to read from the queried element.

E.g. `@ViewChild(`someVar`, read: ViewContainerRef)` will locate the element with a variable `someVar` on it and return a `ViewContainerRef` for it.

Background: With this change, Angular knows exactly at which elements there will be `ViewConainerRef`s as the user has to ask explicitly of them. This simplifies codegen and will make converting Angular templates into server side templates simpler as well.

BREAKING CHANGE:
- `DynamicComponentLoader.loadIntoLocation` has been removed. Use `@ViewChild(‘myVar’, read: ViewContainerRef)` to get hold of a `ViewContainerRef` at an element with variable `myVar`.
- `DynamicComponentLoader.loadNextToLocation` now takes a `ViewContainerRef` instead of an `ElementRef`.
- `AppViewManager` is renamed into `ViewUtils` and is a mere private utility service.

modules/angular2/test/compiler/template_parser_spec.ts

@@ -1506,7 +1506,8 @@ class FooAstTransformer implements TemplateAstVisitor {
   visitEmbeddedTemplate(ast: EmbeddedTemplateAst, context: any): any { throw 'not implemented'; }
   visitElement(ast: ElementAst, context: any): any {
     if (ast.name != 'div') return ast;
-    return new ElementAst('foo', [], [], [], [], [], [], [], ast.ngContentIndex, ast.sourceSpan);
+    return new ElementAst('foo', [], [], [], [], [], [], false, [], ast.ngContentIndex,
+                          ast.sourceSpan);
   }
   visitVariable(ast: VariableAst, context: any): any { throw 'not implemented'; }
   visitEvent(ast: BoundEventAst, context: any): any { throw 'not implemented'; }
@@ -1523,6 +1524,7 @@ class FooAstTransformer implements TemplateAstVisitor {
 class BarAstTransformer extends FooAstTransformer {
   visitElement(ast: ElementAst, context: any): any {
     if (ast.name != 'foo') return ast;
-    return new ElementAst('bar', [], [], [], [], [], [], [], ast.ngContentIndex, ast.sourceSpan);
+    return new ElementAst('bar', [], [], [], [], [], [], false, [], ast.ngContentIndex,
+                          ast.sourceSpan);
   }
 }