refactor(shadow_dom): remove ShadowDomStrategy in favor of @View(encapsulation)

BREAKING CHANGES:
- `ShadowDomStrategy` was removed. To specify the encapsulation of a component use `@View(encapsulation: ViewEncapsulation.NONE | ViewEncapsulation.EMULATED | ViewEncapsulation.NATIVE)`
- The default encapsulation strategy is now `ViewEncapsulation.EMULATED` if a component contains styles and `ViewEncapsulation.NONE` if it does not. Before this was always `NONE`.
- `ViewLoader` now returns the template as a string and the styles as a separate array

modules/angular2_material/src/components/progress-linear/progress_linear.ts

@@ -1,4 +1,4 @@
-import {Component, LifecycleEvent, View, Attribute} from 'angular2/angular2';
+import {Component, LifecycleEvent, View, ViewEncapsulation, Attribute} from 'angular2/angular2';
 
 import {isPresent, isBlank} from 'angular2/src/facade/lang';
 import {Math} from 'angular2/src/facade/math';
@@ -16,7 +16,8 @@ import {Math} from 'angular2/src/facade/math';
 })
 @View({
   templateUrl: 'package:angular2_material/src/components/progress-linear/progress_linear.html',
-  directives: []
+  directives: [],
+  encapsulation: ViewEncapsulation.NONE
 })
 export class MdProgressLinear {
   /** Value for the primary bar. */