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/test/render/dom/compiler/directive_parser_spec.ts

@@ -239,8 +239,7 @@ var decoratorWithMultipleAttrs = new DirectiveMetadata({
 
 var someDirectiveWithProps = new DirectiveMetadata({
   selector: '[some-decor-props]',
-  properties:
-      MapWrapper.createFromStringMap({'dirProp': 'elProp', 'doubleProp': 'elProp | double'}),
+  properties: ['dirProp: elProp', 'doubleProp: elProp | double'],
   readAttributes: ['some-attr']
 });