feat(Directive): convert properties to an array

fixes #2013

BREAKING CHANGE:

Before

    @Directive(properties: {
      'sameName': 'sameName',
      'directiveProp': 'elProp | pipe'
    })

After

    @Directive(properties: [
      'sameName',
      'directiveProp: elProp | pipe'
    ])

modules/angular2_material/src/components/button/button.ts

@@ -11,7 +11,7 @@ export class MdButton {
 
 @Component({
   selector: '[md-button][href]',
-  properties: {'disabled': 'disabled'},
+  properties: ['disabled'],
   hostListeners: {'click': 'onClick($event)'},
   hostProperties: {'tabIndex': 'tabIndex'},
   lifecycle: [onChange]