Added new phone Pivot control

Added new phone Pivot control.
Fixed a property in Hub which was mis-declared as a dataSource binding.
Added the closedDisplayMode property in AppBar.
Merge pull request #25 from spankyj/master

Added new phone Pivot control
Adding existence check for phone

The Windows and Windows Phone versions of WinJS have different control
sets, because of this we check for the existence of a given control
before creating the directive to have the right directives on the right
platforms.
Merge pull request #26 from spankyj/master

Adding existence check for phone
Merge branch 'master' of https://github.com/codemonkeychris/angular-winjs