Fixes bug where the WindowsPhone template will not work in Visual Studio 2013

This change in the __Game.vstemplate will make it so that visual studio 2013 will look for any Microsoft.VisualStudio.SmartDevice.ProjectSystem.Base assembly reference.

Currently I am not able to test this behaviour on Visual Studio 2012.

Alternative to this fix would be to create a separate template for Visual Studio 2013.