Simplify various details around the use of view transforms.
Move the half-pixel offset for bitmaps into view space instead of world space.
DefaultMaterialSet's push/pop methods for the view transform automatically apply the changes.
Push/pop rendertarget automatically set/restore a reasonable viewport.
A DefaultMaterialSet created from a service provider containing a graphicsdeviceservice will create a reasonable viewtransform automatically.
Fixed SynchronousDrawToRenderTarget not restoring the viewport.