Provides Direct2D and DirectWrite to Toolkit's Game class
This is an (unofficial) preliminary implementation that might eventually get integrated in the next iteration of the Toolkit.
The Direct2DService class still has some problems when window gets resized, the origin of the problem is explained here: https://github.com/aybe/SharpDX.Toolkit.Game.Direct2D/blob/master/SharpDX.Toolkit.Game.Ex.WinRT/Direct2DService.cs#L133