feat(core): provide support for relative assets for components

Assets defined for `templateUrl` and `styleUrls` can now be loaded
in relative to where the component file is placed so long as the
`moduleId` is set within the component annotation.

Closes #5634

modules/playground/src/relative_assets/index.ts

@@ -0,0 +1,19 @@
+import {bootstrap} from 'angular2/bootstrap';
+import {reflector} from 'angular2/src/core/reflection/reflection';
+import {ReflectionCapabilities} from 'angular2/src/core/reflection/reflection_capabilities';
+
+import {Renderer, ElementRef, Component, Directive, Injectable} from 'angular2/core';
+import {MyCmp} from './my_cmp/my_cmp';
+
+export function main() {
+  reflector.reflectionCapabilities = new ReflectionCapabilities();
+  bootstrap(RelativeApp);
+}
+
+@Component({
+  selector: 'relative-app',
+  directives: [MyCmp],
+  template: `component = <my-cmp></my-cmp>`,
+})
+export class RelativeApp {
+}