wrong UI rendering of d3d8 games

[RUEEE]

open the in game backspace menu will cause some original UI disappear (like scores)
this is caused by not backup/restore the texture and viewport after rendering.
it's supposed to add the backup/restore of rendering context in thprac_gui_impl_dx8.cpp
like
g_pd3dDevice->GetTexture(0, &g_pOrigTexture) g_pd3dDevice->GetViewport(&g_pOrigViewPort)
and
g_pd3dDevice->SetTexture(0, g_pOrigTexture); g_pd3dDevice->SetViewport(&g_pOrigViewPort);