D2D proto, cleanup mouse handler

Now it uses the Surface class.
D2D proto: begin_draw() clears

Seems that you always have to clear.
D2D factories graduation

plx::CreateDCoVisual plx\gfx\dco_visual.h;
plx::CreateDCoSurface plx\gfx\dco_surface.h;
plx::CreateDCoWindowTarget
plx::CreateDCoDeviceCtx
plx::CreateWICDecoder
plx::CreateWICBitmapBGRA