Fifoplayer depends on the old behaviour of videosoftware (and the other
hardware backends in non virtual/real xfb modes) where the framebuffer
gets rendered directly to the screen.
Really fifoplayer should call BeginFrame/EndFrame when it finished
rendering a frame, but adding this hack back in is simpler.
This adds xfb support to the videosoftware backend, which increases it's
accuracy and more imporantly, enables the usage of many homebrew apps
which write directly to the xfb on the videosoftware backend.
Conflicts:
Source/Core/VideoBackends/Software/SWRenderer.cpp
Source/Core/VideoBackends/Software/SWmain.cpp
