feat(Directive): Have a single Directive.host which mimics HTML

fixes #2268

BREAKING CHANGE:

Before

    @Directive({
      hostListeners: {'event': 'statement'},
      hostProperties: {'expression': 'hostProp'},
      hostAttributes: {'attr': 'value'},
      hostActions: {'action': 'statement'}
    })

After

    @Directive({
      host: {
        '(event)': 'statement',
        '[hostProp]': 'expression'  // k & v swapped
        'attr': 'value',
        '@action': 'statement'
      }
    })

modules/angular2/src/router/router_link.ts

@@ -34,7 +34,7 @@ import {Location} from './location';
   selector: '[router-link]',
   properties: ['route: routerLink', 'params: routerParams'],
   lifecycle: [onAllChangesDone],
-  hostListeners: {'^click': 'onClick()'}
+  host: {'(^click)': 'onClick()'}
 })
 export class RouterLink {
   private _domEl;