[Toolkit.Graphics] Add a check in RenderTarget2D.New in MSAA scenarios and forbid the use of MSAALevel.None
Add GraphicsDevice.GetRenderTargets(...)

and cache current render target views and depth stencil view in
GraphicsDevice
[Toolkit.Graphics] Add comments to GraphicsDevice.GetRenderTargets. Improve efficiency when setting render tagets.
[SharpDX] Add Thread name to TaskUtil.Start
[Toolkit.Graphics] Add GeometricPrimitive Cube, Cylinder, GeoSphere, Plane, Sphere, Teapot and Torus. Add sample Geometrics.Desktop to demonstrate their usage.
[Toolkit.Game] Fix issue with regression when using multiple window, revert back using standard application window dispatching on desktop