fix(toolbar): disable view encapsulation. (#678)

* Disables the view encapsulation for the toolbar component.
  To be consistent with other components and simplify custom styling.

Fixes #676.

src/components/toolbar/toolbar.scss

@@ -11,7 +11,7 @@ $md-toolbar-padding: 16px !default;
   color: md-color($palette, default-contrast);
 }
 
-:host {
+md-toolbar {
   display: flex;
   box-sizing: border-box;
 

src/components/toolbar/toolbar.ts

@@ -1,7 +1,8 @@
 import {
   Component,
   ChangeDetectionStrategy,
-  Input
+  Input,
+  ViewEncapsulation
 } from '@angular/core';
 import {Renderer} from '@angular/core';
 import {ElementRef} from '@angular/core';
@@ -12,6 +13,7 @@ import {ElementRef} from '@angular/core';
   templateUrl: 'toolbar.html',
   styleUrls: ['toolbar.css'],
   changeDetection: ChangeDetectionStrategy.OnPush,
+  encapsulation: ViewEncapsulation.None
 })
 export class MdToolbar {